Problem. What should I do?

On April 13th I contacted a freelancer to do a project for me (a cms for a gaming website). He asked me for 50% of the payment so he could start the project. I paid him $75. He said he would have it done in two weeks. Two weeks passed and I didn't know anything about the project's status. Then he finally showed me the cms' control panel and asked me to pay him the rest of the money because he needed some to pay a bill. We made a deal that I would give him some of the money and he would get it finished on that week. He agreed and I paid $50. He didn't get it done even after two weeks. I told him then that I cancel the project and he told me that he would refund my money.

Over two weeks have passed and he still hasn't refund the money. What should I do? I am sending him messages everyday to send the money and he doesn't. I am in really need of that money. Any help?