I feel very sorry for you, in your position, but it has happened to all of us. Out of the blue, an agency contacts you with a long-awaited opportunity and then nothing. It as if the agency was dangling bait in front of you to see if you will bite. Might i be right in surmising that this agency is one from which you have not heard, or had work, for a long time? I wonder if they are just seeing if you are still around.