STILL debited after canceling contract 8months ago

So in August of 2014 I paid in full for a premature cancellation for a contract with Vodacom. All went well until March this year. They debited my personal account without my permission. I stopped the debit order with ABSA however they are STILL able to take money WITHOUT my permission. I also have just been told that ABSA cannot stop Vodacom from accessing my account. After 2 MONTHS of emails they have cancelled the \ contract "again yet I was debited AGAIN!!!!!! After MANY emails and Every time I call they say I must call back in 7 to 14 days. In other words passing the buck. I do not want this number anymore yet they also insist on making it a prepaid number. I CANNOT understand how Vodacom cannot just leave me alone!! And second of all HOW ABSA cannot stop this from happening again. For some reason they now want to refund me an amount from August yet I was only debited for 2 months. I cannot understand this."""