Sorry to hear that it has turned out to be your car sman66.
If I can offer any advice, that would be to remain calm and friendly, but be clear and firm (and reasonable) in what you would like to occur.
Just remember that the dealer is probably just as frustrated as you at this situation as it's disappointing, costs them time and money, and it's something completely outside of their control too!
Good luck and I hope it comes to an agreeable conclusion.