Vodacom continues debit order after contract cancellation

I have been trying to cancel my Vodacom contract since June 2018. After numerous requests to cancel the contract, I was informed by a consultant at the call centre that my contract was definitely cancelled as at the end of October 2018 and that I would be refunded for the months where the debit order was taken erroneously. On 1 November, instead of refunding me Vodacom again took the full debit order for my contract from my bank account. I personally feel this constitutes theft, as money was taken from my account without my permission and my deliberate instruction to not do so.