Cartrack trouble

The biggest problem was the day that I decided to install cartrack in my car. Since day 1 having trouble with the unit. Every month I need to phone to either reset the unit or need them to send a technician to come and put a new one in. The specialize technician were at my car 2 week ago and today I needed to phone them again and on their system it shows that the unit need repairs but they will not phone you to ask if something is wrong. I ask if they could send a specialize guy out again and according to them it will take 48 hours for it to be booked and I am the one that does not have a car that are in running order. Since I've put cartrack in about 18 month ago the already have to replace the unit 6 times. This is really getting to be a big problem, and I want this to be taken out of my car but they want me to pay cancellation fee, but for what...TROUBLES