You'll need an expert evaluation on the condition of the vehicle, a vehicle history report and direction from a local consumer protection attorney who handles lemon law and auto fraud matters. Find someone competent to handle this type of matter here:
I am not an attorney in your state, but most states require that frame damage be disclosed to a consumer when they purchase a vehicle at a car dealership. I agree that you will need to get a Carfax Vehicle History Report (if you do not already have one) and have the vehicle inspected by a mechanic to confirm the frame damage. But, to get a definite answer regarding your legal rights what your next steps should be, you should contact a local auto fraud attorney in your state. For a list of consumer attorneys by state, click on the following link: http://www.ohiolemonlaw.com/locate-a-local-attorney.shtml. Best of luck, Beth
This answer is for general purposes only and does not establish an attorney-client relationship. The law in your state may differ and your best answer will always come from a local attorney that you meet with privately. If you need a Consumer Law attorney, click the link above to find a Consumer Law attorney near you.