Serve notice and then pay again!!

On the 25th February 2016, I phone Mixtelematics to cancel my premium with them and they asked me to do so in writing which I did (same day) via email.<br> <br> On the 28th February 2016 (Sunday) I received a statement for March 2016. I phoned Monday 29th March 2016 to find out as to why am I receiving another statement for the following month since I cancelled. Kegomoditswe Modise was the first cancellation person I spoke to, he told me that they would have to debit again next month as we pay in arreas. I told him that I pay in advanced and even my statements indicate that I pay in advanced. He told me he cannot help me as I am ill informed. He said I serve 20 days notice and still pay!!!! How does that work??? Really???<br> <br> I then asked to speak to the supervisor whom was George Mothutsane who reiterated what Modise had said. So I told him that I would send him a copy of my statement so he can see that I pay in advance. After I had sent it to him, he never responded nor took my calls. He would not apologise nor acknowledge his fault.<br> <br> I have been paying for the past 3-4 years and I want out now. I don't want mixtelematics to debit my account EVER AGAIN!