unless you're filing a suit against them and dont want to mar your character or theirs, theres no reason to be secretive about their identity, theyre secretive enough due to the ambiguity of the internet and user names.
You're not donig them any favors keeping it quiet. Bad sellers on
ebay are bad sellers for as long as possible simply because no one voices it.
Personally when I get screwed on
ebay (which has only been twice) I make it a point to spread that knowledge around until
ebay finally does something about it. The last seller that ripped me off finally got their account deleted because I wouldnt shut up about it on the forums.
I think it evened out considering that seller CALLED MY HOUSE with the number
EBAY GAVE THEM to tell me to drop dead and i should watch my back all because I said I was reporting them for refusing to refund a return I KNOW they received.
Dont be quiet about stuff like that. Bad things only happen because they can happen in secret.
Thats all I have to say about that.