Hi @Anonymous but this isn't customer services.
I suggest you raise a complaint with O2 as we cannot assist with account issues, sorry
This happens far too regularly and the community is full of similar posts if you search. It's ok them saying it has been sorted out but as the system is automated to a great extent, someone needs to be responsible for entering the correct information. Finding the right someone shouldn't take multiple calls over multiple months.
Other than the above advice, Google CEO O2 and email his office. To me you are due a generous goodwill gesture.