According to the Texas Deceptive trades practices-Consumer protection act article 23 :"The failure to disclose information concerning goods or services known at the time of the transaction and was used to induce the consumer into a transaction whom otherwies would not have entered had the information been disclosed."
-specifically cited in the example "... or, when an auto dealer knows that a car has been in a wreck and fails to disclose that to the potential buyer."
I realize this is a Texas State statute, but most states have this exact consumer protection act, and all states have similar legal protection from "bait and switch" or a coerced sale.
Forget the BBB and the Attorney General and find a lawyer to draft a demand letter using your states consumer protection legislation to force the dealer to do right.
In Texas he would either have to 1) reverse the transaction or 2) pay 3x diminished value to you as a settlement.
Good luck (I'm in the middle of one right now)