Go to Solution.
Try manually searching for another network.
Or you probably have a roaming bar on your account, in which case you need to contact O2 to remove it. All numbers in these guides
Guide: Coronavirus Community Help and Support
Guide: How to find help & contact O2
*The Game Is On*
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Change your data apn to "mobile.o2.co.uk"
Track usage, upgrade and get support with the My O2 app