Since he opened a claim you have a few days left.
I would get all your facts together about him having 2 accounts (pretty sure that's against the rules on eBay unless that's changed)
Show the proof he has shilled his own auctions and go from there.
You could even link to this thread and the FCB thread too because PayPal will look at them.
Good luck man and I hope it goes in your favor
Currently Collecting Dolphins, Nationals, and Alabama Football Players in Alabama Uniforms