Support haven't answer on my problem

You weren't robbed, you were foolish.

Don't bother if you clicked on "This is a gift" button. They won't return items.

A) You are on SteamGIFTS!
B) Trading is HERESY!
C) If you were really robbed you'd be better off contacting Valve, or in some cases, Volvo!

Not robbing if you agreed to it Kappa

cs go items worth 250€ + .... Just how??? Your account was hacked or something, or you just gave him those items? If your account was hacked then you can get those items, but well I gues you just gave them away to him, so I don;t know, if you will ever see them again.

I highly doubt valve will return your items in case you did the trade yourself. If you were hacked they can see that someone logged into your account from an IP other than what you would be expected to log in from, and then they might help you, but if you just sent someone your items with that person promising to do something for you in the future, then they probably won't do a thing, as it's going to be very hard to actually prove that you had a deal.