I m sorry i never thought he would have mentioned wrong steamtrade profile on his steam. I just went to his steam profile through the chat window and saw there Steamtrade profile and clicked and this page opened up.
Its the following person someone helped me to find out him. I wish i had seen his reviews earlier so i could avoid that scam.
He is Fraud and Scam. After taking my game he gave me Invalid Key and Unfriended me and not responded after that.