Struggle to stop a debit order after contract cancellation

I have been trying to cancel my contract since October. After plenty phone calls I have made to customer care and several branches, the services I got from Vodacom is absolutely terrible. After I have made so many phone call they kept on telling me I have received the benefits. I was told that my last debit order will be in October and that my contract was definitely cancelled. Vodacom has again debited the money from my account. I personally fee this is theft as money was taken from my account without my permission and after plenty instructions to cancel my contract and not to renew the contract.