The calls and tactics are always changing.  They target the old landlines more so since mostly elderly people are the only ones with them anymore.  My mom is 94 and has medical equipment hooked to that landline so I didn’t want to cancel it but the calls got so bad that the caregivers could not filter them all . After some major issues that occurred with scammers, I  found a device on Amazon’s that will only let calls go thru that you first program into the machine.  The first day after installing the machine there were 70 some calls that were sent to scam land. . After a year they have dwindled to less than 10 a day now.  Once they get someone hooked the calls multiply rapidly.