Nothing much can be done. You gave out your account info, therefore you are the one who allowed yourself to be scammed.GM's won't return any items, unfortunately.
Thank god game system reminds you every x time not to give your login details to anyone...
And this would be the reason why the only person who has my account stuff is my husband, and it's only for emergency purposes only. And seeing as we live together, if he tries to steal my shit, I can sharpen a couple of knives for him, if you know what I mean...The only thing that may happen is the guy getting banned. And even that's not a guarantee. Just take it as a lesson learned.
I was lol'ing at this so hard because of the nice comment but I don't even give my wife the logins. She has her own and can work at it like I did if she wants to play. To the OP. it sucks but all you can do is move on and use this as a learning experience.