Cancelled contract debiting me

I phoned Vodacom to cancel my contract I October. I requested that they give me the amount I need to pay to close of the account (as I wanted to close the account earlier). I paid the amount in full before the required date. I went to the vodacom shop at Westgate so they could upload the receipt and process my cancellation. Vodacom debited me in November and December which I allowed. Now they have debited me in January. WTH is wrong with Vodacom. I CANCELLED this contract and even told your retentions department that I no longer want the contract.