Take him down man! Lol.
In all honesty though, you shouldn't have done business with him in the first place. I mean he was a Junior member perhaps with little to no positive feedback from the community and had a small amount of posts indicating a lack of interest to contribute to the community. Going through what little posts he has would've also given you an idea of what kind of person he is. Next time do a more detailed search of the person before agreeing to make any transactions with him/her.
Good luck with getting your bitcoin back!