Invalid ? (?)

Scammer steam ID: halo force
thats all i could get because he blocked me. D:







I was just casually trading, looking for an unusual horseless headless head-taker and i see this guy selling it and trade with him. He could tell i wanted it bad because of my stupid reaction which gave it away. The offer started at 4 ref and he said that i would need to add more metal so i put in a hat and said put in 5 and then i added s.stickybomblauncher, s.directhit s.sydney sleeper and s.sniper and a medic misc and alien swarm parasite. There is a screenshot linked to it for proof.

Please Please help me i'm not concerned to much of my items but i want justice.