if you have had his driver license information, you could go to police station to report this fraud with the other evidence such as the posting on caraigslist. At least you might know who the guy is and where he lives. once you confirmed his address and himself, you could take him to small claim court to get your money back. However, even you win the case, how to get money back is still an challange. what you could do is not to give up and have great patience.