Worst service by Netstar

I am with Netstar Car Tracking on my vehicle, called to arrange a new contract for an additional new vehicle. A week later I have have not received a call to schedule a fitting appointment and they know very well this makes my insurance null and void and when I call the lady assisting tells me they can only assist after 4 more days. How can I wait any more longer and what if anything happens within this day. When I called Netstar to complain they tell me there is nothing they can do and I can call retention to cancel. Unfortunately I can only cancel the new unit but not the existing one's contract. How do I continue to do business with them (Obviously binded by contract) when I know they gave me the worst service and treatment ever while putting my financial life in jeorpady.