Did you have an attorney representing you in the transaction. If yes your attorney should proceed with an action against the sellers attorney. Also, I would immediately contact the Bar Association and make a claim against the selling attorney. If you did not have an attorney representing you and a realtor, this was very foolish and now you will have to go through a lot of trouble yourself to get your money back. Are you familiar with the terms of the contract you signed? If you weren't properly represented and protected you may have signed a contract saying that you would lose your deposit if you couldn't get a loan. The sellers attorney should not have been representing you and should have advised you to get your own counsel. That is in the state of New York. Outside of the state of NY it is the realtor that draws up the contract and along with escrow the transaction is completed.
I still think you can receive assistance from the ethics committe of the Bar Association. Best of luck.