Dice Scammed Me

I lent Dice my knife in June multiple times, the last time I asked for it back and he said it disappeared, I believed him and tried to be nice, he said he would buy me a new knife, in 3 days and he didn't he then in August tried to pay me w/ his account which I accpeted to check the trade history and saw it was traded to a gambling site bot, I confronted him and he told me the truthand i confronted his parents i was willing to give him alot more time to pay me back but then today his parents said they wont pay back anything, I also noticed that he defriended me. The knife was a M9 Bayonet Stained Well Worn.

HERE IS HIS PROFILE

Please help.