O2 app

[Jasmine04]

cant log in

[Oxonian]

@Jasmine04 

Try logging in on the web. At the top of this page, click on the MyO2 link :-

If that works, uninstall the app, reboot your device and reinstall it.

If the web route doesn't work, you'll need to call Customer Service on 202, or on 4445 if you are a PAYG customer :-

Guide: How to find help & contact O2 

[MI5]

@Jasmine04 

Try online https://mymobile.o2.co.uk/
If using the app, try deleting, rebooting phone and then reinstall the app.
This is a customer to customer community, not O2.
You need to contact O2.
Message them on Social Media. Facebook (https://o2uk.co/O2CFB) , Twitter (https://o2uk.co/O2CTW) or Instagram (https://o2uk.co/O2CIG) or give them a call on 202 or 0344 809 0202 (contract) 4445 or 0344 8090222 (PAYG)
Unlikely that you'd get help in store, but may be worth a last resort try.