Check that you have the correct settings - the link below shows how to set it up depending on your phone @Dg2810.
https://www.myapnsettings.com/2020/07/o2-apn-settings-2020.html
If everything looks ok, try your sim in another phone (if you can).
Otherwise pop into your local o2 store or give customer services a call on one of the numbers in the guide below:
Guide: Coronavirus Community Help and Support
Guide: How to find help & contact O2
Please note, this is not customer services and we cannot access your account. Do not publish personal details (email, phone number, bank account).
Link to our guide on how to contact them can be found here
