Bitcoin requires trust since transactions cannot be reversed and escrow services generally aren't used.

The only recourse against seller fraud is reputation.

This guy, Yankee/Charlie, stole money from me and did not acknowledge my issue.  From this thread it's pretty obvious that he's stealing bitcoins from others.  He's dishonest, so further appealing to him is just a waste of keystrokes.

The only thing one can do is to call him out in public for it so that he can't scam others.