Debit for R9000.00 (not authorised) and they sommer take 10 debits

I have cancelled and called and cancelled and called. Yet Cell C still Debit my account, 10 times to a total of over R9000.00. How is that ethical? I DO NOT owe cell c R9000 for ****. If there is another debit order from my account I will be taking legal action. this Should be cancelled as I have requested numerous times where I get an SMS that it will be a month to Month contract. I have already left Cell C, i want nothing to do with Cell C, now leave me and my bank alone!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!