Who the hell is this?!

I only picked up because I live in Utah, so it COULD have been someone I knew.  There was no one there.  My guess is it's some sort of robo-call.  Utah has so many call centers now.  I will soon stop answering calls from my own area code!

Repeated calls from various numbers reportedly for a free alert device - how do I stop these unwanted, unsolicited telephone calls?

Relentless calls. This number will be reported to the proper authority.

I answered and there was no one there.  I called it back because it was local, but the call wouldn't go through.  I'm hoping by reporting this that the calls will stop