Someone keep calling unknown and not saying anything

5 times today alone

I keep getting a call from that number and from 203-347-3178

I called the number back thinking it was someone I know ( I am from CT). When I called the number back there was an automated message saying the number doesn't exist , and then I tried again and it rang several times and then hung up. This number called me twice yesterday and three times so far today starting at 7:30 am!