Was the claim for a lost/stolen handset and sim @Alex33 ?
If yes, there will be a bar on your account which you need to get customer services to remove.
You can call them on 202, or message via social media - links below.
Facebook (https://o2uk.co/O2CFB) , Twitter (https://o2uk.co/O2CTW) or Instagram (https://o2uk.co/O2CIG)
If not, then it could either be a sim or phone issue.
Try your sim in another phone, and another sim in your phone.
If the sim works in another phone but the other sim doesn't work in your phone it's a phone issue.
If the new sim works in your phone but your sim doesn't work in the other phone, it's a sim issue.
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 Do not publish personal details (email, phone number, bank account).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
