Someone from this number has called several times with out leaving a message.

Someone from this number has called several times leaving a 4 second blank message.
Caller ID: Message from an unidentified caller (2102490540)

Some one calls the work phone and says his name is John from Medical Services Dept and tells me it's not solicitation... he is calling to help people get medical compensation. He keeps telling me his is part of a Government office and he wants to help.  I told him to take the number off his database and he keeps talking. I asked for his direct number to report him to our compliance dept so he hung up.  I'm sure he'll call again tomorrow.

someone called from this number - no message.  Can not ring back as number is always busy.