call but no message

Several calls from this #. Never leaves a msg. ID says 'unknown name'

Same voice I heard last week... I told that person their scam (fund the poor shot up police) is all over the internet, so now they're calling me on another number.  Go call your mommy.  I'm sure she's SO proud of your entrepreneurial behavior.  NOT

Answered with hello. Nothing on line. 3 seconds passed, other side hung up.  Given other messages here, difficult to conclude anything else but that the callers are engaged in a scam.

Has called me many many times,but I've never answered.  Today I did, and the guy was talking fast, sounded like he was on a speaker phone.  Wanted my birthdate to verify "who I am talking to".  Basically told him he was nuts to try such a scam, I'd never give out ANY info like that to a strange caller.