Horrible service doesn't care about their customers

It's been months now since I've been for my device to be fixed and no one has gotten back to me regarding this, bare in mind the I am driving a car that has faulty device and should anything happen to me they will not be able to locate my car. This is not happening for the first time and matrix doesn't seem to be bother, the only thing that they are good at is taking my money every month. Number 2 I never get any calls when my battery gets removed which that for me is a huge problem that I also reported but still no help received number 3 the stupid App doesn't work. This is worse service ever matrix doesn't seem to care about their customers at all, i want to cancel this stupid contract because it is not serving its purpose really. I am very disappointed in the service that I have received and highly concerned about my safety driving a car that I not track able