unauthorised debits done **********ly

A contract was entered with cell c without my knowledge or permission. I informed cell c about the matter and submitted relevant documentation once I realised that money was being debited from my bank account. I made contact with cell c in Bloemfontein Lochlogan/waterfront shopping mall, whom the Consultant was able to assist me with the submission of thr paper work. However, cell c from their ***** department is dragging their feet on doing their part. I was informed that cell c has declared the contract cancelled however, the cell phone company still debit my money at the end of the month. The so called investigation has been going on for months now. I cannot keep on reversing unauthorised debits as this affect my credit history, please assist. While I have been a loyal customer to them with all of my payments done in time I don't expect such sloppy service, 'for the one authorised contract I have with them'.