Get onto ebay then and get them to sort it, too much of that shit goin on.
Matt
Been there myself and absolutely nothing you can do about it. Ebay simply suggest the buyer/seller negotiate, what use that is I'll never know.
On a similar note, my DX crankset sold for £295.00 a couple of weeks ago, the same night I was offered £450.00 and though tempting my honesty won through.
You'll always get bad apples.