Decent letter, valid complaint. The only part that is absolutely fake is when he writes that he is in the market for a new car in the next year.
Anyone that was in the market for a Mercedes and had the means to buy one would not be all that concerned over a $50 Morton's card.
If he was in the market for a Mercedes in the next year it would not be contingent on anything other than the vehicle. The sales people do not care because they pegged him for someone looking only for a $50 gift card and not a serious sale, otherwise they would be all over him.