A pity that it happened to you.
So far i have had only good deals. Publicly i have sold just a few domains but all without problems. And just a few days ago i sold another 3 privately in a matter of minutes, after we arranged the price, i got the money and transfered the domains in less than 10 minutes.
Also i have bought some domains without problems.
I think the key is in choosing wisely with whom do you do trades, and to have some back to hold your domains if you don't feel well with selling them for the price you can get or to a person who you are not sure you can trust.
Good luck and wish you some good trades.
