Is this a new problem or has it been going on for a while @Lukasz1984 ?
Have you tried the standard fixes (turn your phone off an on, remove the sim clean it and put it back in)?
Take a look at some guides below that might help.
Guide: How can I sort out my network issues?
Guide: Is the network down for me or everyone?
If nothing in those helps then you might need a new sim - which means a visit to your local o2 store, or you can either call customer services on 202 or 0344 809 0202, or message on social media:
Facebook (https://o2uk.co/O2CFB) , Twitter (https://o2uk.co/O2CTW) or Instagram (https://o2uk.co/O2CIG)
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 Do not publish personal details (email, phone number, bank account).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
