Cartrack UNHAPPY Fleet Customer

We have been having an issue with one of the tracking units in our fleet and have after about 3 weeks still not been able to get it resolved through the Cartrack Fleet Department. They are simply not understanding our issue and keep on saying that there is nothing wrong with the unit. They are not providing constant feedback and we have to constantly follow up. After numerous requests they have now offered to book the unit in for repairs at a cost. How are we supposed to use the vehicle while the unit is booked in for repairs? What about the possibility that the unit has come loose and this might be the issue? How do we get a technician out to check and inspect a Cartrack tracker, this seem to be impossible!