Scammer steals gold in trade window

Hi, I'm progressiv of Lordareon, player **** is a known scammer and he just got unbanned (according to people who wisped me), I didn't know that and I traded a signet of the traitor king for 4,7k gold and I saw 4,7k gold in trade window, but I received only 470g, then the player ignored me when I asked the gold.
Can you do something?
What should I do?
Thanks
Progressiv

If you have some kind of proofs (screenshots or video) you can report it by making a support ticket in game. Otherwise there is nothing you can do about it. In any case, you can not get the gold or item back.