I'd suggest a polite, factual letter to Audi USA which begans with something like "Your advice and assistance would be appreciated". Outline the problems factually, objectively, without displaying anger or frustration. cc at the bottom to whoever protects consumers in your state and send them a copy with a cover letter asking for their assistance and advice. Try to avoid using "I" or "We" as much as possible, particularly at the beginning of any sentence. Close the letters thanking the recipients for their time and attention. Send the letters Special delivery with return receipt. Also send a copy of them to the dealer. He will want to avoid explaining to state officials and/or Audi USA, especially if it is his fault. You need to come across as a reasonable person who is knowledgable and being wronged. Don't lecture, don't tell Audi how great you think their products are, they know that your selection of a new 35 plus grand Audi is your endorsement and a compliment to their product. Finally, be prepared to tell them what you think is a reasonable solution to this problem. Be polite, don't call names, grumble under your breath, make snide or disparaging remarks. Let the dealership be the son of a *****; you be the swell old boy. Get a neutral person to read your letters before you send them. Your letters present you as well as your side of the dispute.