Billed for a Vehicle that I no longer have.

I traded in my Toyota Fortuner in Dec 2014 and even though I have logged several notices firstly to cancel the subscription in Dec 2014 and that even to this day I am still being billed for a vehicle I don't even have. The lady named Pinky at Vw Mccarthy durban(@ the tracker division) called me every day before I could purchase my new vehicle because she needed a sale but when I call her now for help she doesn't take my call and never bothered to return my call. As for Nomsa, She was terribly rude over the phone when I logged in a cancellation. I logged in a cancellation in Dec 2014 and again 3 months ago. I'm paying for a vehicles tracker that I do not have for 9 months. I want a refund for all the months tracker has been taking my money for nothing!