Mystery voicemail scam can hit without your phone ever ringing

It starts quietly. Your phone buzzes with a voicemail notification. The strange part is that your phone never rang. Then it happens again. Before long, your voicemail inbox is filling up with messages you never heard come in. That's exactly what Mike from Westport, Connecticut, is dealing with right now. He wrote to us saying:

"I am so upset. Every 20 to 30 minutes, I am getting voicemails, but what's weird is my phone never rings. After blocking the number, it just rolls over to a new source number. When I go to play the message, there is no audio. Is this a scammer just trying to get me to call them back? Not sure what the endgame is here. What can I do to stop this from happening? I really appreciate your help."

Mike's experience has the hallmarks of automated spam activity, but there is an important distinction. A voicemail that appears without your phone ringing does not automatically mean a scammer used a special "ringless voicemail" system. Your phone's call-scree...