Well, since he uses market alot i better alert you all!
At first i bought 3 Arma 2 OA Keys with him, 1 was banned, but that was Okay! and he asked me for 2 Infestations Steam Gift!
This was ok!

Now he offered me 10 Arma 2 OA Keys for 2 Infestations Gifts, 1 Infestation with gold and 1 Rust!
He gave me 12 keys, all banned and deleted me from steam!

Trusting him was a mistake, its all good!
Just showing his true face...

Good luck you all!