I would want to know what eBay's rules are for this type of auction. You may have to submit the dispute to them. I agree that it looks like you were bidding on 2 money clips, but their rules for multiple auctions might cover this type of problem.

It seems like it will end up in eBay's lap anyways, since no immediate solution would seem to satisfy all three parties.

Frankly, I would suggest submitting it to eBay before the seller reaches some kind of separate deal with the other guy. In other words, time may be of the essence.