Misinforming clients about changes to their contra

I have had a pay as you go contract for years - in 2011 requested that I wanted a contract with my Pre Pay no,<br> I received accounts for the next two years for a contract I did use as they did not change the no to my pre pay.<br> I tried again this year , when my pre pay was blocked , when into store to have it unblocked - found that it had not been changed to contract, but I had a new contract with a new number - The various departments that were contacted could / or would not unblock the phone ,and of cause had no knowledge of my request to have my pre pay changed - and they would not cancel my new contract that I was duped into.<br> Now I have no working phone ,just a bill again for the next few years for a non existing service, Client services just maintained it was not them ,it was someone else to blame