Close
pleas submit reports to steam rep, and a steam support ticket. Simply - rep and leave a link to the steam rep post (with proper formatting and evidence) is going to help more than this will because few people dealing with him will see this in time or remember if they did but they will see the - rep post.
http://steamcommunity.com/id/MeSSaR
The deal was I give him 8 TF2 keys in return for a game, but he never held up his end of the deal, he also promised a refund, but signed off when I asked him about it.
https://support.steampowered.com/attachment_tickets.php?id=2528695&display=1
https://support.steampowered.com/attachment_tickets.php?id=2528699&display=1
Don't be fooled by his rep, he is a scammer.