There is normally a reason they are not responding to you - but I do think a quick phone call back should always be made by selling agents of short sales (or any listing for that matter). Do you have a buyers agent who has tried to call both the office and the listing agent? That would be the first step.
Unfortunately, the bank is not going to answer any questions you may have about the property. To gain access to be able to talk to the bank about a property, the owner has to sign documents stating the individuals who are able to talk to them.
Please let me know if I can be of further help - I am a realtor in Barnstable County.