Cancellations department cannot handle the public

Cancellations department is pathetic, when contacted telephonicly they will confirm that it is done, but soon enough they will sent you a account with services that was not part of your original package but then you pay it because you assume it is your last account, a few months later you receive a letter of demand but you have not received any accounts to prove that the services was activated. I have been battling for nearly 5 months now to cancel this number I am not using at all. All of a sudden I see now on my account I have a fixed voice service that should have been only a ADSL line. But the account has been cancelled according to the call center so I guess that I will soon receive another letter of demand.