Misrepresentation of deal

In 2008 I purchased a Dodge Nitro and they sold the car to me as brand new whereas it was a used car that was bought by another client who drove it until 3000kms then they reversed the kilometers. When I discovered and confronted them they agreed that a mistake was made on their side so they will trade in that car and sell me a C180 Mercedes Benz at cost which also to my shock I discovered it was in an accident and fixed prior to me taking delivery of it which they didn't disclose to me. Now this car is giving me problems and they not interested in assisting me.