Bad service.

I was using cartrack for my red Renault Kwid and i traded the car in and got an audi a4. i called cartrack so that they can get the unit from my previous car and come put it in my new car, they came back and said they managed to get the unit from the other car and we scheduled for them to come fit it in my new car. which they never did, i called and called spoke to a lot of agents and each time i speak to them they have no clue as to what happened in the previous call. so now they expect me to pay for the passed 7 months were i did not have a tracking device so i refused. last month a lady called me from the accounts departments asking me if they remove the arrears for the months i did not have the unit, will i be able to continue with the contract and i said yes, she then said she will get back to me and am still waiting for her even now. i asked them to send me all the recordings between me and them and they said they will get back to me on that and am still waiting as well. my account keeps being debited and i reverse the debit order all the time which is damaging my credit score. please assist.