Multichoice keeps on debiting my account, despite a 0 balance on my statement!

I did a change of ownership of my DSTV decoder to my boyfriend's name after we moved in together, for the sake of having extra view with his DSTV being the main decoder (I thus switched my DSTV account off completely, and he is paying around R40 per month extra on his DSTV account for extra view). I phoned DSTV towards the end of August to switch off my DSTV, which they did, but the magtape already went through for the payment of September. A friendly telesales lady told me that she can do nothing for the magtape, and that I need to revere it from my bank - which I did. I even received a sms to tell me that my DSTV was cancelled upon my request. From October, DSTV started deducting my account again. I phoned DSTV asking them for a statement, and THERE IS NO ARREARS ON MY ACCOUNT. I had to reverse 3 unauthorised deductions of R747 monthly since then. I received a sms today, informing me that DSTV will be appointing an independent consultant to gather the money i still owe them... I DO NOT OWE THEM ANYTHING!