I've dealt with numerous members on here over the years, buying and selling, and luckily never experienced behaviour like this. I think it's fair to say these type of incidents are few and far between.
Reading the recent posts above, I wouldn't be surprised if the loco had already been shifted while it was being advertised here, that's if he even had it to sell in the first place. If that is the case, he's lower than a snakes bollox, and ought to be ashamed of himself.
Hopefully, this gets sorted for you sooner rather than later.