Refund on my last debit order

I was on contract with Vodacom which was due to end on 31-10-2017, on 26-10-2017 my account was soft locked and called Vodacom call centre and they advised me to make cash payment which I did. At the end of October they still went and debited me full amount yet I have already R1344 on the 26-10-2017. I have been calling Vodacom since to get them to refund me my money and they keep promising me the refund but not delivering on the promise.