Am I wrong here?

I don't blame the guy. He had a customer there with cash, so he sold the trailer. All he knew of you was a phone call. If he knew the other guy was coming to look at it then he should have told you, but it was his trailer, he can sell it to whom he wants. I've been told countless times someone is coming to look at a car, or I'll be back tomarrow, etc. and lost money because of it.

And dealing on a handshake only worked with Andy Griffith in Mayberry, and thats only because everyone knew everybody. You don't know anyone that calls you from a add on the internet, which makes that handshake hard to account for.