Since you were dealing with QS, you *did* send first; he may have pretended to send first, but was really only sending to himself?
Now this reminds me of the movie Interstellar...
Kind of offtopic, but kind of related:
People often appear in the Just-Dice chat asking if I have CLAM for sale for BTC. I often do. Instead of telling them "send X btc to address Y" I'll use the built-in escrow system. It will tell them the amount and address, and hold my CLAMs in escrow until they send the BTC. In a sense I'm escrowing my own deal since I own JD and by extension its escrow system. But there's no fee, they are willing to send first anyway, and I don't think anyone has the expectation that JD is a neutral third party.