Got 2 calls,  long silence- voicemail left. No message

Got 1 call with a silent voicemail

Received call at 11:54 from this number. silence from the other side.  While I was repeating 'hello', I get another call from the same number (while the first one is still connected).  I hang up the first line to switch to the second line but again, silence!!  Very annoying!

Received a call at 1819 Wednesday 10-29-08. A few moments of silence, then someone pressed a tone button for several seconds and hung up.

Strange.

no message