Good luck with it, chances that people will return your items are 1%.
You could try to ask the guy who you did the trade with, he should know if he had lost any gold.
Some people won't anwer, they are playing deaf. Sadly, majority people who are clanless are crap people and if you make a mistake a it depends of them you can forget about your items and accept the loss.
Also, devs simly don't care. After all, marketplace is free and it's beatiful metagame (by donkey himself)..