You can sue--if the seller committed fraud, or made (either through words or by actions; e.g. rolling back the odometer) material (or important) misrepresentations (or lies), that is illegal, and you could potentially sue for either 1) monetary compensation (e.g. to receive the difference in value between a vehicle with 99k miles or 161+k miles) or to rescind the sale (return car, get money back). In some states, this sort of consumer fraud could, depending on the circumstances, even entitle you to additional compensation. You don't say how much you had paid; if you paid a few thousand dollars, get a lawyer to help you; for several hundred dollars, consider suing in small claims court and representing yourself to save legal fees.