Sorry for the long post! Anyway this is what is happening that I am in

Sorry for the long post! Anyway this is what is happening that I am in. My life partner and I purchased a vehicle on 11/22/21 in Tennessee. We exchanged our BMW the vendor didnt present our stuff on schedule and the endorsement terminated. I reached them a few times and recently continued to put me off. Presently here we are 2 months after the fact and they are requesting new pay check and for us to sign another agreement with awful terms. What do we do?????? In the event that get a lawyer is the recomenation what kind?