Because your phone number is between (000) 000-0000 and (999) 999-9999. Robo-dialers pick an area code, a prefix & dial every number. Listed, unlisted, on the DNC - it doesn't matter. You're being called by criminals. foreign or domestic, take your pick. Criminals have only one interest, and it isn't following the law. It's to steal your money, or personal information.