Invalid A guy scammed me With some Low Strange W.-s and with a CD-KEY from 'steam'

Hello!
A guy scammed me with some low strange weapons and with a CD-KEY (he said it is acceptable in steam /Serious Sam 2nd encounter/)
So, He said to me If I give 2 hats and a strange knife , he give me a Game in steam /Serious Sam the Second Encounter Classic/ and he give 1-2 stranges (i dont remember because it was last month ) , I gave the stuff, and he gave me His stuff, and the cd-key, I tried to Accept the CD-KEY and that was invalid, He deleted me , and never could get back my items (Oh, and he stolen my friend's Picture while we trade, so I thought he is my best friend)
NOW I FOUND THE GUY! But couldn't take screenshots :/
His steam ID .: http://steamcommunity.com/id/shdv
Mine .: http://steamcommunity.com/profiles/76561198025570344/

May 20​

You traded with -=4E=- | ๖ۣۜShDw.. 3:36pm​

+​

Strange Loch-n-Load, Strange Big Earner​

–​

Strange Knife, Carouser's Capotain, Old Guadalajara​

Then we trade, and hegave me the CD-KEY from 'steam' ,and Went offline (removed me)
Sorry for my bad english
Have a good day
Please help me /I posted it last month, so copied and found the scammer, and Again did this Thread

As this thread clearly states,

That combined with the fact that you have supplied no screenshot evidence of the sort leaves me no choice but to invalidate this report.