Unbelievably bad service from Tracker.

I am really frustrated. We are being billed for a vehicle that we no longer have. CB08NFGP. We called Tracker. We told them we were buying a new vehicle and asked to have the tracker removed from that car. They told us they dont remove devices and said we would have to purchase a new tracker for the new vehicle. They explained we should cancel CB08NFGP and replace it with the new tracker for DX69GTGP. For about 6 months now one has tried to help us but you keep billing us for CB08NFGP when we have bought a new one for vehicle DX69GTGP going according to your instruction so that you can cancel CB08NFGP. No body has tried to help us, everyone is passing the buck and then i asked Pierre why he hasnt given us feedback and he said well he agrees we should just cancel our 6 contracts with you people? I am tired of this. No body takes responsibility and keep pushing us in a corner saying its our fault. How can it be our fault when you send us the documents to fill in?

Why is the vehicle we keep cancelling still being invoiced to us? CB08NFGP?

I am really really not impressed with your service at all. I want a new invoice as per attached.

Its literally like im speaking to stone cold thin air.