Can I legally take action such a crime ?

i have sold my online game account i.e my facebook account linked to the application (game) to a guy online who accepted to pay xxx.. amount of money for my account. after i have shared my login details the guy have scammed my account he changed my accounts password but not paid me the promised amount. and blocked from all the things from which I can contact him. can I legally take action against him? i have no options left i don't know what to do. i have invested a lot in that account.