I'm saddened by your loss and turn of events. You should consult an attorney for any remedies under the law and your listing agreement.
As for others reading this thread. I strongly encourage you to seek professional guidance on short sales from agents that specialize in the process. You do not want to be an agent's short sale experiment. You should also seek agents that are "hands on" with your file. You can easily find professional, trained agents by searching for agents in your area that hold either the CDPE (Certified Distressed Property Expert) or SFR (Short sale and Foreclosure Resource) designations. While not a guarantee of performance, at least these agents have gone the extra step to become familiar with the short sale process.
Byron Lohman, CDPE, SFR, CCIM
Prudential CA Realty
Palm Springs, CA
CA Lic #01272085