Sucks OP but I agree with those who advise to give it to them full blast! Both barrells for that unethical BS. I'd give them one last chance and follow it up within 24hrs with a Fedex letter from someplace legal directing them to be in default of their legally binding eBay contract and to remedy the situation OR pay/sue for damages to include legal fees AND the sale of the vehicle at cost per auction when won! Then I'd go and pick up the car myself WITH the tv news to "capture" the story and ah ensure the correct respsonse and treatment of the new purchaser and his wonderful new car! I'd also let BMW NA and BMW AG know what I planned to do and basically make it so uncomfortable and profit losing for that particular dealership that they'll be happy to see you and your M3 drive off into the sunset!
Just have the car checked as soon as you get it back to CA to make sure they didn't leave you any unpleasant surprises! LOL
'15 F80 M3 sedan (Blk Sapphire Metallic) - Mine #1
'14 Cayman S (Agate Gray) - Mine #2
'13 Harley Davidson Dyna Custom - born to ride