If you mean which account your direct debit comes from, yes @Paul52
Log into your account, then click on "My o2", then "Cards and Direct Debits" which is the 4th column.
If you scroll down slightly you should see a box with the current details, and an option to change them.
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 Do not publish personal details (email, phone number, bank account).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
