Speak with your broker for help.
If you are not really an agent, then maybe you should hire one. This is a very good example of agent's education and value.
Best of luck to you!
As far as collecting the emd for damages, you may not be able to collect and keep the emd for damages. you cant get blood from a stine is the old saying, you could bring a civil suit for damages if you can prove to a court that you were damaged. The threat of a suit may move the buyer along to sign the release and you both move on.
Make sure everything is in writing, dont do anything verbally, keep records...