Fitment, negligence complaint against cartracker

The company don't care about it's customers but only money. I had a car which I sold last year, as I had a contract with car tracker, I requested that they uninstall the tracker and reinstall to my new car, it took them forever to do the job when they have deducted the removal and reinstallation money on top of my monthly premium. They managed to remove the unit from my old car but for 4 months they've failed to fit a tracker to my car to date, they have been deducting their premiums all these months, everytime I reach out they set a far appointment and don't come in the day. If I move money to the account immediately there's money they deduct. I've been asking them to cancel if they not willing to come to me but they just dismiss me. I'm very disappointed and angry with them