As daft as it sounds you might have a roaming bar on your account.
Call customer services on 4445 (if possible), or use one of the numbers in the guide below - you can use Skype and one of the freephone (0800) numbers.
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 Do not publish personal details (email, phone number, bank account).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
