1- You are being Yo-Yo'ed. It's an old dealer trick. THEY finance you and then say (truly or not) that they cannot get financing for you. In essence, they have not "assigned" your sales document to some business they usually work with and they translate that into you (skipping the part about your mom) have not been financed, which is simply untrue.
2- Since the deal required a LOT of papers, unwinding it should be done in writing. If they truly wish to unwind, it will be hard not to comply, but, make them do it in writing and to send you all the terms they wish to unwind by.
3- They cannot make you sign a new deal, so, either they unwind and give you back your money and your car in exchange for theirs or they do not. There is no requirement for you to sign a new deal.
Do not "talk" to them any further. Communicate only in writing.
Good luck with it.
Attorney Kaufman offers you VERY sound advice. Your kind of fact pattern is one of the more common situations on Avvo. You should stick to you guns and either agree to keep the current arrangement or to unwind the entire deal. If the dealer has "sold" your old car, then they are stuck with the deal you all agreed to.
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Mr. Kaufman and Mr. Frederick have nailed it. You (and your mother) made a deal with the dealership. If they unilaterally decide that they want to modify the terms of the agreement, you have to agree to any such changes. You are not required to agree to different terms. As suggested, you should only communicate with them in writing, and be sure to keep a clear log of the communications. The dealership either needs to honor your original agreement or unwind the entire transaction.
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