Canceling of Fibre with Vodacom and Vumatel

I have called Vodacom middle of August to cancel my fibre I have with vumatel as they are my ISP. The debit order went off on 1 September and I gave vodacom a call and they told me it would be the last debit as I was supposed to give a month notice which is fair enough. I leave it and then this morning I see vumatel debited my account again. What must I do to get this fibre cancelled and for them to stop deducting from my account as this is not the first time I am having these issues.