I would still be cautious and concerned about the guy. $500 or so that he received from both of you would still not justify for a scam.
I have a little story on something similar. I bought an old used laptop from a guy on e-bay. Turned out the laptop the guy sold me was stolen - all of somebody's personal info/e-mail correspondence was still there; even more - the laptop came without any kind of attachments (e.g. power supply, mouse, software, etc.). Luckily, I had a pretty good deal going on this. However, this guy started receiving negative feedbacks for some pricy items (brand new laptops, projectors, etc.). Turned out, he even copied others' listings and pictures and when people paid him, he would send packed telephone books instead of laptops.
I guess I was the last guy who legitimately bough something from him. Another interesting scam story (or at least its conclusion) you can read HERE