Paying for a tracker i don't have

I'm paying for a tracker that i don't even have installed in my vehicle. The problems began when i sold my vehicle and they failed to get the unit from that vehicle with 2 months notice i gave them. So now i don't have any tracker but i'm still paying R220 every month. Secondly, my contract is for 2 years ..currently I'm paying this amount for 3 years. Witbank branch manager (Nico) promised to sort out this issue. It has been 11 months and I haven't even received a phone call. I even phone the head office but received not cooperation and the message i get is the will come back to me. They also told me they can not track my vehicle because the account is inactive but i will attach proof