A Scammer Came Acalling

“Mr Morris?”
“Whose calling?”
“Your internet provider”.
“And who is my internet provider?”
“I’m calling from” (the caller proceeds to mention an internet service provider (ISP), but not the company who provide me with both my web connection and telephone line, and, not surprisingly, I hang up without another word)!
Given that my home telephone number (landline) is unlisted in the telephone directory, heaven only knows how these scammers obtained my number! My ISP has been hacked, several time...