Remember in the future to always use escrow if possible when making a higher-value exchange like this. He states in his OP that he would use devthedev as an escrow if needed, not that it makes any difference to a scammer of opportunity.
It appears that user suchmoon has already left him negative feedback, having noticed that others have complained. I am going to leave feedback as well and link it to this post so others can take note.
Also, this post should be in the "Scam accusations" section. Perhaps a moderator can move it for you. Good luck.
Yes. Lesson learned.
And it looks like it has been moved. Thanks to whomever did. And thank you too!