So i sold stuff on ares for 15$ (not much always something).
Ok after 1 day from transaction i got letter from paypal to back cash.
The guy said he didn't use paypal (not authorizy user or something like that) and want he's many back. (i made phone to paypal that this user recaived his items ingame)
So paypal back him his many.
Well thx, from now i can trade only via paypal + ebay or to very trusted players.