Recently purchased a Mercedes that was a trade in ...

Recently purchased a Mercedes that was a trade in on their lot. In negotiations, they said they would fix a spot on the bumper that was discolored and a few other cosmetic details. Later when I went to pick up, the spot on the bumper was untouched and they claimed that was never discussed. On the way home from the dealership, the check engine light came on and we checked the oil level to find out it was bone dry. Two weeks after taking the car home, the battery had to be replaced. I really liked the salesman we did business with, he was very friendly and willing to accomodate our budget. However I'm still disappointed they didn't stick to their promises in negotiations.