Solved: This happened to me and I just went to the O2 shop and they got it solved.
1) I have recently moved home and my bank address wasn't up to date, so lady at O2 put my old address.
2) Check for discrepancies on you bank and personal address, wrong postcodes or spelling mistakes in your name or age
3) If this is not your case it could also be you registered two accounts in the same email address
Hope that works.
