Improper Format Dota2 Trader Scam

Scammer
|steamID: RaMbØ
|steamID32: STEAM_0:0:60325333
|steamID64: http://steamcommunity.com/profiles/76561198080916394
|customURL:
|steamrepURL: http://steamrep.com/profiles/76561198080916394

Victim
|steamID: PixieBaby™
|steamID32: STEAM_0:0:50183889
|steamID64: http://steamcommunity.com/profiles/76561198060633506
|customURL: http://steamcommunity.com/id/04yatz
|steamrepURL: http://steamrep.com/profiles/76561198060633506​

This guy scam my sparrow set for 15$ steam money... I ask him how the procedure then he invited me to make trade so i accept it to show what going on then in chat menu a message appear like this (RaMbØ Send 15$ For Trade Items To Your Inventory) I don't know how he do that. Then He said I make trade after that he offline and blocked me.
Here's my inventory trade history screen shot. Trash this bad guy on steam and Dota2

I don't have Screen shot of chat because he blocked me i cant never see this guy on my list in steam beta.