Account problem

Cartrack has not stopped harassing me for the past few weeks about a cancellation fee outstanding that I did not cancel. I've spoken to numerous people explaining to them that I have not cancelled a device but moved it from one car to the next. The vehicle in question has been sold 3 years ago.

I don't know who to speak to anymore I've tried their managers that doesn't work there counts that doesn't work they do not communicate or make notes on your file to say what's going on and then they call you three to four times a day and you have to explain everything over and over. Now they even start calling me after hours. 1 hour after I explained everything to the one person the next person will call and ask the exact same questions. If there is anyone that can assist me in this please contact me