Getting the dealer to owe up

You obviously have a difficult situation. You would be very wise to make an appointment with the dealer principal for a face to face meeting. In that meeting be polite and business like. Be very definite in what you want the dealer to do and the time frame in which it has to be done. If the dealer does not give definitive answers, then reiterate until you get a definite answer all the time being polite and business like. Prior to that meeting ascertain if your state allows for audio recording with one party approval. If they do, then consider carrying a miniature voice recorder to that meeting.

If that meeting fails, you have no recourse than either to sue the dealer or pay for the repairs and move on.