Ive had similar situation few tears back. I lend about $3k to one of mu best fren in australia... However that guy didnt pay me back for almost a year. I try to be rude, bother him and even said bad words but nothing worked. Later I became nice to him and ask to pay back in small amount what ever he can. And that worked for me. So i would recommend to not take any hard action tight now.. Be nice and ask gor whatever he can pay back. And $500 is not alot of money to take legal action. Application for sueing smbody is around $100 depending in states.