Did you release the Bitcoins without getting paid, or did the buyer just cancel?
The buyer just cancelled.
I mean, because the buyers in general are pretty flaky.
Yeah, I know, I use craigslist a lot.
The only reason I'm annoyed is that I figured people who flake would accumulate negative feedback; that would prevent a scam like this from working. Unfortunately localbitcoins.com's feedback system is broken in a way that enables this scam.
If there is absolutely zero penalty for (or record of) flaking you can make quite a nice profit via opportunistic flakery.