He fucked you Bro, deal with it

there's no way to recover your fg back (unless what someone said that the SCAMMER himself decides to pay what he owes you)

when you make a scammer accusation against him, mods will open a case and they will revised the evidence against him and etc. if (or when) they determine that he indeed scammed you, they will lock his gold and all the amount of fg he has will disappear for good. in that case escenario, there is NO way to get it back, the fg is simply gone

next time check their join date and ask for a mediator until you get one (unless the other decides and agrees to go first)

sorry this happen to you bro

I dont see any reason why not to give that fg back to him, if fg was still on scammer's account of course