calls from Unknown

Scum bags

Who IS this?  Do you know?

Received call, said hello, nobody on the other end.  Thought the call was dropped, so tried calling back.  busy.  busy. busy.  Got through, but heard dialing.  I suspect it's an auto-dialer of some sort.... maybe one of those fax machine spammers???

keep getting calls , nothing at all on other end.  will eyeball caller id and just not answer anymore.