I think that you have waited quite patiently and for long enough.  It is time that you hired an attorney to sue him for the return of the vehicle.  Forget the text messages.  They are most likely not going to be accepted as proof of his intentions to purchase the vehicle or a contract for the purchase of the vehicle to the extent that you can call them a "contract" and apply the law as it related to a breach. So let's just get it back to you and have you return it to the dealership.  Now, speak with an attorney in your area as to filing the matter and obtaining service  upon him of the legal papers in order to obtain a judgement of possession.  Good luck to you.