Webwork - 2:36 pm on May 5, 2010 (gmt 0)
We're a bit outside the bounds of the Domain Forum Charter but, as the saying goes, somtimes you gotta let your hair down . . if you still have your hair, that is. :P
One legal issue that pops into my hairless head is the statute of frauds [en.wikipedia.org]. Read it. It touches on the importance of putting your agreement into a signed writing, i.e., a contract.
Please read Domain Forum Charter -> Trademark and Legal Issues [webmasterworld.com] before going any further. In part, the info you find in the Charter is there for your own protection.
Also, we don't usually allow gripe-fests . . but, if true . . this is a pretty good one. :P
As my legal secretary would say, when I was battling a particularly tough adversary, "Sucks to be you!" In other words, what she was saying to me was "IF making the big bucks were easy . . we'd all be rich and retired . . So, deal with it".
In your case, consider hiring a lawyer in the jurisdiction where your purported seller resides.