Cell C - Bad service - refuses to cancel contracts

Do not do business with Cell C. In previous years I have had good service with cell including canceling contracts at their fulfilment, new contracts etc. This is not the case with my latest contract which expired and I emailed cancelation. I have sent at least 4 different emails and no less calls, canceling the contract at completion. I even paid out the contract as it was not needed. After contract expiry cell c continues to bill and puts through unauthorized debit orders. I am very disappointed with the service and I would recommend all to stay clear.