if i was in your position i'd ask my sister for his info on where he lives and go beat his ass...i'd probably play house cuz no one f*cks with my family...if she doesn't tell then a little scare tactic and force will make your sister tell...then do as i stated and proceed with the ass beating...

if you don't want violence then i know for a fact most people who came from hong kong are rich so settle it for some cash!!!!!!! then beat his ass...