Bill

[Brown22]

I'm trying to pay my bill. It keeps saying there is something wrong 

[pgn]

Contact O2 Payment Management on 0800 902 0217.

And take it on advice to set up a direct debit, it is the norm for O2 Contracts, @Brown22 

Good luck!

[Oxonian]

The mechanics @Brown22 of setting up a direct debit are herein :-

Guide: How to Pay Your Bill (Contract)