Cartrack failed they clients even single day !!!!

Please people be aware of cartrack, they don't give a good service...I sold my car and give cartrack a 7 days notice to come and swap the tracking unit from one car to my new car, with my continuesly communication with cartrack they never come and do the swap, my car was sold to a new owner....they failed me as a new client and now they demand a monthly payment for the tracking unit that I don't have anymore or they will blacklist me 😡😠😠