Horrid Cell C bills for a canceled account

Yet again, despite the fact that my data account has now been cancelled after 5 attempts of trying to cancel an expired contract. On the 1st of March 2015, cell c went into my bank account and tried to debit 6 times more than the amount the initial contract was for. Cell c really is thee most despicable company I have ever had the displeasure of dealing with. Is there a legal mind out there who can advise on what legal route is available to me?<br> Tried ICASA and they were no help at all. Any advise would be greatly appreciated