Who called from 3015602061

This caller called me numerous time. Every time i pick up the phone a recorded "Hello?" plays and then the phone hangs up. If you call the number back it claims you've won a $100 prepaid credit card. If you press 2 they claim you'll be on their "do not call list" and will never call you again. Who is this and is this a legit number?

This number has called several times, all I get is a males voice that says hello, then the phone cuts off.