Who called from 8155179267

No message left. Unrecognized #

Answered because it was close to where I am. I said Hello, in a low voice. And they hung up

Just got a call. Said "Hello" but no one was on the line. Answered because my child is in that area on a trip.

Called on my cell phone.  Do Not Call is not working.  "The number you have reached is not in service." when I called it back from a different phone.  But the voice and speech didn't sound like the phone company, and could have been faked.

Called called, 7/18/16, at 4:30 p.m., while we were eating dinner. I decided to answer since we know people with 815 area code. However, I said 'hello,' three times but no one replied.
Why in the world would Bozo's bother people, any time of the day/night, only to disconnect?
I wondered if these scammers listen to people's voices, targeting senior citizens.