They don't want to end my contract

I have been calling Cell c to end my contract for the past few months and it seems not to go anywhere but they keep trying to retain me. I don't want to be retained and I don't want to work with cell c anymore. My service was R150 pm , but they once debited Over R2000 for out of bundle rates, but also the consultant had promised me that when I hit 0, the service will stop, which didn't happen.... my contract ended in June but they say that I still have to put a notice to end it... what kind of **** is that? We haven't signed any new contract, I don't use their services any more... but I keep getting a bill ????????? ? Also the keep sending statements that can't be viewed... why don't you send a normal PDF?