The funds that are currently being held cannot be released until both Seller and Buyer agree in writing. The fact that the Seller is refusing all contact with his Agent makes it very difficult. Your first course of action should be to meet with your Broker & Realtor and ask for your Broker to speak with the listing Broker, maybe they can come up with a plan to reach the seller. Even if it means knocking on their door. You also have the option of speaking with a Licensed Attorney who specializes in Real Estate law. I wish you luck!
If that doesn't work, you need to get your agent and their broker involved and see what other options you may have, or get a court order.
Start with getting the name of the asset manager's at the Seller's bank.
They are going to get the property anyway and have to deal with it.
So your agent needs to get in touch with Seller's agent and work with the
Asset folks. Also, the Sellers agent needs to communicate with the
Title co. that the funds need to be released to you in writing.
Depending on the Real Estate company you used, they must have a legal Department
so your Agent should already be in touch.
This happens quite often, so it should all work out.