called,  i did not answer    --   they left a silent msg  - no sound??

we have significantly reduced the unwanted/unknown callers by pressing "on" then "off" on the phone; all the caller gets is a click then  a short beep. It doesn't cost a thing and gives us great satisfaction!  

Number calls repeatedly; when call is answered, there is no one on the line and then the call disconnects.  If you attempt to call the number back, the phone rings briefly and then an automated voice says, "Goodbye," and the call disconnects.  Caller ID lists the call as coming from Prosper, TX with no name or company listed.

I too am get this caller several times a week  If you call it back there is a creepy recording of a female voice saying "Goodbye".
Wish someone could make them stop.

unsolicited call from security company to a registered no call cell phone number.