Cell C ***** division is useless

Cell C's ***** division provides absolutely zero feedback. I opened a ***** case and sent all the required documents to them. After more than a month, I have heard absolutely nothing and Cell C billing dept has the nerve to call me to ask me to pay arrears. I have been disputing the debit orders and attempting to stop the debits - however every month they just take more money. There's no way to close the account (according to their knowledgeable accounts and retentions staff) and my bank account and credit score continues to suffer. Every time I have to dispute or stop a debit - it costs me money and my credit score drops due to unpaid account.