This dealer apparently has no integrity. They did not have a 335i allocation slot available (or if they did they gave it to someone else) and strung you along for weeks. Call around and see if you can find a dealer with open allocation for a 335i to be built in GERMANY in October and you would have the car before Thanksgiving more than likely. You could also check board sponsors, I think there is at least one in NY.
You should not leave the dealership without your build number... anything else is BS.