Verified
It's ok. But they really should communicate in how many days/hours their sim will be active. I spent hours with no connection, cause my old sim died and UNDO wasn't active yet.
Company replied
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The registering process was a pain, it seems that I tried when they had a multi-day outage. I finally managed to get my e-sim and it seems to work. Will update the rating after further testing.
Company replied
Verified
I just transferred to UNDO and it feels like an upgrade. I have added a bunch of stuff too like beehives, clean water, schools etc and it is still under 15 euros ! It was also super quick, I have orde... See more
Company replied
Reasonably priced services. Socially responsible company. Runs on Orange network, which works best where I live, at the time of this post (could be different elsewhere). Reached out for support when... See more
Company replied
Company details
Written by the company
UNDO is Belgium’s first climate-neutral mobile operator. We combine affordable mobile plans with real impact: CO₂ compensation, reforestation in Congo and Belgium, and Zero Waste on all our subscriptions. With us, unused data, minutes and texts don’t disappear — they roll over to the next month. No waste, no fine print — just honest mobile. Starting from €4/month.
Be a bit more sustainable with UNDO
Written by the company
- Measure your impact, and reduce it!
- The UNDO app measures your carbon footprint from using your smartphone in real-time. Users can see the sources of the emissions and also take steps reduce it! Conscious consumption is sustainable consumption. What you cant reduce can be compensated by supporting carbon removal technologies that ensure removal and long term storage through UNDO Removal in the mobile application.
Contact info
Chaussée de La Hulpe 177/11, 1170, Brussels, Belgium
- +32490461999
- support@undo.be
- undo.be
Join UNDO, make the planet better!
4.0
Great
321 reviews
Replied to 100% of negative reviews
Typically replies within 1 week
Verified
It's ok
It's ok. But they really should communicate in how many days/hours their sim will be active. I spent hours with no connection, cause my old sim died and UNDO wasn't active yet.
6 October 2025
Reply from UNDO
Thank you for your feedback! Unfortunately It was taking so long because your previous operator didn't liberate your number. Once they did this, we've immediately activated your number at UNDO. If you have any questions, feel free to reach out to us! The UNDO team
Verified
Omg this exists ?
I just transferred to UNDO and it feels like an upgrade. I have added a bunch of stuff too like beehives, clean water, schools etc and it is still under 15 euros ! It was also super quick, I have ordered it yesterday and it was open today.
6 October 2025
Reply from UNDO
Thank you for your positive feedback! We're happy to hear that you're satisfied with our service. If you have any questions, feel free to reach out to us!
The UNDO team
Fine despite some registration issue
The registering process was a pain, it seems that I tried when they had a multi-day outage.
I finally managed to get my e-sim and it seems to work. Will update the rating after further testing.
6 October 2025
Unprompted review
Reply from UNDO
Hi,
Thank you for your review! We appreciate your feedback and strive to continuously improve our service. Could you contact us on support@undo.be? We will resolve your issue then.
Kind regards,
The UNDO Team
Verified
Reply from UNDO
Thank you for your positive feedback! We're happy to hear that you're satisfied with our service. If you have any questions, feel free to reach out to us!
The UNDO team
Verified
Good service
Wratten application was not easy but the service afterwords was excellent.
24 September 2025
Reply from UNDO
Thank you for your positive feedback! We're happy to hear that you're satisfied with our service. If you have any questions, feel free to reach out to us!
The UNDO team
Did a proper job
Did a proper job. Replied quickly and very helpfull.
16 September 2025
Unprompted review
Reply from UNDO
Thank you for your positive feedback! We're happy to hear that you're satisfied with our service. If you have any questions, feel free to reach out to us!
The UNDO team
Invited
Reply from UNDO
Thank you for your positive feedback! We're happy to hear that you're satisfied with our service. If you have any questions, feel free to reach out to us!
The UNDO team
Verified
Reply from UNDO
Thank you for your positive feedback! We're happy to hear that you're satisfied with our service. If you have any questions, feel free to reach out to us!
The UNDO team
Verified
Reply from UNDO
Thank you for your positive feedback! We're happy to hear that you're satisfied with our service. If you have any questions, feel free to reach out to us!
The UNDO team
Reply from UNDO
Hi,
Thank you for your review! We appreciate your feedback and strive to continuously improve our service. Could you contact us on support@undo.be? We will resolve your issue then.
Kind regards,
The UNDO Team
Invited
Adding 5€ without a previous notice…
Adding 5€ without a previous notice that my payment didn't pass and I need to fix it in certain period of time. And if I don't fix the payment in that period it can be added, but added directly is nonsense. I will start looking for a better alternative
26 September 2024
Reply from UNDO
Thanks for your sharing your review.
UNDO always sends out all invoices on your 'registered' email id. UNDO also sends regular reminders via email if your invoice is not paid to the 'registered email id'. Invoice payment is also available in the mobile application. On top of this we give at multiple weeks for you to clear your payment.
In your case this was not done and so you were charged the extra amount. If you are facing issues with making payments then please send us an email at support@undo.be. Describe your issue in detail. Provide proof that you tried to pay and the payment failed. We will verify your claim and check why the payment of your invoice did not go through, and based on our finding we shall see if the extra fees can be waived off.
Regards,
Team UNDO
Invited
Reply from UNDO
Thank you for your positive feedback! We're happy to hear that you're satisfied with our service. If you have any questions, feel free to reach out to us!
The UNDO team
Invited
Great service, great impact, great price
Great service, great proposition. I love how it’s affordable and focuses on being climate friendly.
26 September 2024
Reply from UNDO
Thank you for your positive feedback! We're happy to hear that you're satisfied with our service. If you have any questions, feel free to reach out to us!
The UNDO team
Invited
Reply from UNDO
Thank you for your positive feedback! We're happy to hear that you're satisfied with our service. If you have any questions, feel free to reach out to us!
The UNDO team
Invited
Reply from UNDO
Thank you for your positive feedback! We're happy to hear that you're satisfied with our service. If you have any questions, feel free to reach out to us!
The UNDO team
Invited
4G network is erratic on Luxembourg border with France and Belgium
Most of the time it works alright but I get multiple service interruptions daily when crossing borders to the point that my phone can’t load Waze directions for minutes.
2 October 2024
Reply from UNDO
Thanks for your review. Service interruptions are common for all mobile networks and more so around bordering regions! Moreover, UNDO uses the Orange network which is a major network in your region and have not faced this complaint, and has very little control on this. However we value your input and will try to work together with our host operator to improve the situation.
Kind regards,
Team UNDO
Invited
The premise was great but failed
The premise was great. Plant a tree on my behalf just for using their service. When I first signed up, I didn't get any service for over a week. Then when I contacted them to ask why, they said they needed a copy of my ID first.. Why didn't they say so when I signed up?? If I never contacted them, I never wouldve had any service and they still would've charged me. At first, the service was great. Then after a few weeks I noticed I wasn't able to send any pictures, so I contacted them again and was advised that mms is a separate add on that I need to pay for.. What is this? The stone ages? Of course I wasn't going to do that, might as well just use WhatsApp. Meaning, I barely even use this service, so really just pay 'just in case someone I don't know tries to call me'. What a waste of money honestly. Their website is horrible! It never works! I don't even get any emails about my invoices. When I contacted them about that, they just forwarded me the past invoices. But I'm still not getting any new ones, so they didn't even fix that issue. This was the last drop. I'm going to cancel my service unfortunately.
16 April 2024
Reply from UNDO
Thanks for your detailed review. It helps us improve UNDO!
We regret the experience you have had with us. Indeed we had issues at the start but those have all been addressed now. We are also improving our onboarding for new clients. As for sending pictures most users use 'Whatsapp' and other media such as 'Telegram' which help you send images free of cost using just your internet connection.
We have also upgraded the website now. We can confirm that all your invoices are mailed to your 'registered email id'. Moreover, we have also improved the invoice payment feature and you can directly pay your invoice via our mobile application or the self care portal.
In case you still cant find your invoices please send us an email to support@undo.be, with your UNDO mobile number. We will resolve this issue right away! Lastly, as a gesture of respect for your support and patience we would more than happy to offer you some compensation to still have you as a part of the Undo family.
Kind regards,
UNDO Team
Invited
Good company
Really good internet, great software, and affordable price. I just want you to offer new deals, for example 80 GB, 100 GB, good, at a cheap price, so you can compete with the other big companies.
1 November 2023
Reply from UNDO
Thank you for your positive feedback! We're happy to hear that you're satisfied with our service. If you have any questions, feel free to reach out to us! The UNDO team
Happy using UNDO services
Reasonably priced services. Socially responsible company. Runs on Orange network, which works best where I live, at the time of this post (could be different elsewhere).
Reached out for support when undo.be website was down and I could not manage my subscription, response was not instant, but they came back and resolved issues within 1 day, which I find perfectly acceptable.
Good services overall.
25 September 2024
Unprompted review
Reply from UNDO
Thank you for your positive feedback! We're happy to hear that you're satisfied with our service. If you have any questions, feel free to reach out to us! The UNDO-team
Invited
I could not and cannot find how to…
I could not and cannot find how to upgrade (immediately) when 100% of my usage was reached.
27 August 2024
Reply from UNDO
Hey, thanks for your question. We are here to help you out.
You can add more data to your subscription by activating the 'Data Add-On'. You can do this via the self help portal(www.wsc.undo.be), or, via the UNDO application on your smartphone. Follow the below steps in order to find and activate the Add-On:
1. Log into your account via the application or self help portal
2. After login look for the 'Show Me' button at the home screen and tap on it.
3. here you will find the telecom as well as other value added services from UNDO.
Hope this helps, and if it does could you revise your review to a better rating.
Thanks and kind regards,
Team UNDO
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