Some telemarketingj

Hangs up after  a "beep-click" which is a hallmark of a robodialled call. The "scrooge/David Copperfield" type slavemasters give recently out of jail or East Indian poorly paid minions in a boiler room  or at their crash pad a used refurbished computer dialling machine with a list of names and numbers. The shills get a pittance commission on the number of referral hits which may be to scammers or a group of legitimate businesses such as solar power installation contractors. If the person called sounds young and businesslike, not someone likely to be elderly, "netted" or scammed, they hang up.