Trackless Tracker

A Tracker device installed in my car was faulty, ended up damaging my battery. The car was towed to the dealership workshop where the fault was diagnosed in the presence of a Tracker technician. The device was subsequently taken out by their Technician. During the time I had no device, they continued with the monthly debit order for 6 months. After which they offered me an upgrade, which I took up. Oh, by the way, they paid for a new battery at the time of the fault. Last year when I needed to cancel their subscription, I was told to pay a cancellation fee. I refused, telling them to use the subscription they had billed me for when they were not servicing me. Surprisingly, they now have no record of the faulty device incident and all the telephone recordings between myself and them have vanished. I went to the dealership to get a transcript of what had happened and sent it to them, still they are refuting the evidence. They now want to "view" my car, and see if that initial device was ever taken out. I don't trust them to touch my car. If they can't find the recordings which they claim to have, what will they do to my car?