I hired somebody off your website. Who did a bad job

I hired somebody off your website who took my money went of on holidays and came back. I sacked him. He also put somebody - a stranger in my house who was doing the work piecemeal, claiming that he was his uncle. This man didnt speak english and also did sub standard work. I have had to hire other peope to fix things. So want my money back off this person. I even over paid our agreed amount and spent unnecessary money. Where do I go from here?