Funny that I'm getting calls from this number being I just changed it over the weekend and it's not listed, no one has it. Scam, prank, whatever. It's ridiculous that we have to go through this when they call, yet you call back and the call cannot be completed.
Your new number is someone else's old number. The previous owner changed his number to get rid of these calls.
Robo-dialers can be programmed to call every number in an exchange, in an area code, or in the entire North American numbering plan. An unlisted number will not protect you from a robo-dialer. Yes, robo-dialers are illegal for most uses. That's one of many laws the scammers break many times each day.