The real estate agent HAS to know the consequences of of a seller backing out of a signed contract after accepting deposit money. It is strange indeed. Go to the agent's broker IMMEDIATELY and simultaneously get a referral from the base for a qualified real estate attorney. Something is awry here.
Every area has a local multiple listing board and every state has a commission or agency that governs and monitors real estate practices. If you have a USO or Red Cross office near you, I would also call them and your Congressman there. Your status in the military may also prompt quicker action. THANK YOU for your service, sir. God Bless You and your family, and hang in there.
Sry for the double post ;-)