I would contact the dealer and ask if they received payment, and whether they have negotiated it. I would also ask whether the car title was applied for and if you are sited as the owner. If you received all the documentation you claim you received, you probably have a good cause of action for breach of commitment. You should contact a lawyer who is a civil litigator. Bring all documentation to the lawyer.
No lawyer-client relationship exists. This answer is intended for discussion purposes only. You must obtain legal advice from your own attorney.