I hate to say it but there's really not much you can do nor can a GM due to your personal error in bazaar listing prices. It sucks he'd take advantage of a simple and easy to make mistake and not work out a deal with you. All I can say is be more careful next time =/
But really, this isn't much different than someone that refuses to pay back for AH based errors and overbids. Does not really warrant a player warning thread.