I'd ask where you live but I feel that is more an in person conversation than one for here.
Time to chain the wheel to the door or your house?
In regards to the GPS, I would seriously be talking to them about their liabilities and the fact that they were charging for a service that they knew wasn't functioning.
If talking directly to them fails, getting some legal advice might be good. Or take it to Fair Go
Glad to hear you have a car to use and sorry to hear about your dog
Perhaps update the Police about your neighbours theft attempts, so they can paint a better picture of what happened, if you haven't already.