There could be a number of reasons for that @Kevin2483
Is your bill up to date? o2 are swift to turn off sims if there is an outstanding balance. Contact the payment management team to talk to them - call them direct on 0800 902 0217 (you can use Skype as it is an 0800 number).
The opening times are:
Monday to Friday – 8am to 8pm
Saturday – 8am to 6pm
Sunday – 9am to 6pm
Other things to check - does your sim work in another phone? Or someone else's sim in your phone ? That would confirm if the sim or your phone is the issue.
There are more things to check in these guides:
Guide: How can I sort out my network issues?
Guide: Is the network down for me or everyone?
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 Do not publish personal details (email, phone number, bank account).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
