Multichoice insurance Bills after cancellation and refuses to write off the debt

I have been with muiltichoice for years, and under my contract I was also paying for the dish insurance. A couple of months ago, I called the contact center informing them of my intention to terminate my contract and thus at the end of that month, I requested the debit orders against my account cease. The whole conversation was recorded and the termination was set in motion. My account was still debited at month end, which I revered. To my surprised I am not getting threatening text messages and emails about the "supposed areas" against my name. And how I will h=be handed over to debt collectors. I have called the insurance and yet, they do agree that it was recorded that I called for cancellation, however they are failing to write off the amount which was clearly billed to me in error. I need the account cleared to zero and closed as per request.