in february i gave a good friend's brother $1000 dollars for a pontiac grand prix. since then he has given me multiple excuses as to why the car isn't ready, promised to send me the VIN number and never done it and, recently, ignored my calls and text messages. it was supposed to be a simple exchange between friends, so there were no papers signed or anything like that but his sister did witness the exchange and is willing to support me in any way. what is the best way to get my money back?