Kjuubiiz SCAMMER take care!

On "Trades" there is my topic about humble leftover keys.
There is a player called "Kjuubiiz"
http://steamcommunity.com/id/kjuubiiiiz/
He marked me as a friend and started to trade...

Vazallus: Hi! What can I do for you?
Kjuubiiz: Hi, u have just cause collection?
Vazallus: yep!
Vazallus: :)
Vazallus: What can you offer for them?
Kjuubiiz: Maybe u need Rust, left 4 dead?
Vazallus: Rust is more needed :3
Kjuubiiz: rust - cd key, left 4 dead - gift.
Vazallus: okay
Vazallus: I copy paste the key for you after you tried it, you can send me. :3
Vazallus: 7E7WV-B3FVW-BZ0FW
Vazallus: enjoy
Kjuubiiz: okay, u need rust or l4d?
Vazallus: rust
Kjuubiiz: 1 sec
Vazallus: okay
Kjuubiiz: CFCCP-9RM6C-EKYL3
Kjuubiiz: thanks for trade
Kjuubiiz most Offline.
Kjuubiiz jelenleg offline, üzeneted a következő belépéskor kapja majd meg.
Vazallus: Uhmm sorry but it looks like you sent me a wrong key its a hitman key. Can you send me rust key? until you don't send me you will be flagged as a bad trader/scammer thanks!

So I does not mind If you try keys maybe you can activate it still.

THE Frustrating thing about this little wker is the following:
I'm thrustworthy... no matter what I copied the key as an act of honor.
He's sent me a key which is worked fine, but I already owned a key of hitman.
Anyway. If you starting to deal with him, please take care.
These ones are the worst.
He tried to scam with paypal as I see on the topics.
Update* He deleted my comment from his profile. And disabled comments also.

Anyway... I know I can thank to myself and It's a bad idea to throw a key first but please. Where is honor? Where is fair play/trade? Ahh come on!
Feel free to check my trades, and also good luck and be careful out there fellas'!
http://www.steamgifts.com/trade/7RKp8/hmany-keys-for-steam-wgames-only

Bye!