Billed 4 times for Tracker in 1 month

I am livid with Tracker. Firstly, I had to cancel my tracker contract because my car was sold to the dealership. Secondly, I had a new tracker unit installed in my new car on the 26 November 2018. I was billed R1158-79 on the 30 November. I was billed for cancellation, as well as the old car's tracker in advance, and a pro rata amount, and still the new tracker in advance. This is *******. The old vehicle is no longer in my possession but I was billed for tracker. You pay tracker in advance so why was I still billed for December when the old vehicle was sold to the dealership. I've sent numerous emails and I called in. I was told by Simphiwe Ngubane that I would only pay the cancellation fee and tracker in advance for the new unit installed. I paid tracker in advance for the old tracker unit and it was not used for the entire month. There I had to pay for another month for the old tracker. This is absolute *******. I am going to cancel the new contract with tracker, put a stop order on Tracker and join Netstar. Absolute *******.