My 02 never works for some reason

[weejack]

It keeps saying something went wrong

[jonsie]

If you are trying to log in to the My O2 app

Instead try the web version 

https://accounts.o2.co.uk/signin

If that works then delete the app, reboot phone and reinstall 

If none of that works then 

You can call O2 on 202

Or use the social media links below