I answered the phone with my usual business greeting, there was 10 seconds of silence then the call disconnected. When I called the number back a recorded message said, "Nobody's available to take your call at the moment." There was an opportunity to leave a message (I remained silent while writing notes) then options to listen to, re-record or delete the message I left and finally an option to speak to an operator by pressing 0. When I pressed 0, the call disconnected. The mystery of who called will NOT keep me awake tonight.