I get calls about nonexistent car warranties, student loans, accounts in collection, mystery nephews in foreign jails, and so forth. I don't answer unfamiliar numbers and delete the messages, but don't bother blocking their numbers because they're nearly always spoofed.
Obviously they catch enough fish in these nets to make it worth their while. Case in point:
About five years ago a Jamaican ring started fleecing my widowed father-in-law with a "you've won millions, but it's going to cost a bit to get the money released" story. They got at least $10,000 in cash from him before a daytime caregiver became suspicious of the increasing number of incoming phone calls. He listened in on an extension, realized what was happening, told my FIL to hang up NOW, then called my husband. Between the three of us, my FIL, the bank and the police, we patched together what was happening.
We immediately forwarded my FIL's phone calls so they would only ring on my number because these creeps called relentlessly - all hours of the day and night. They were threatening, frustrated that I wouldn't let them talk to my FIL and furious with me. Their clumsy tactics and lace of sophistication would have been laughable if it weren't apparent that they were more sophisticated than my dear, sweet FIL.
Clearly their prey were the trusting, confused, and folks with diminished cognitive capacity. Truly slimy.
Desperate to keep the money flowing, a couple of their operatives brazenly showed up at my FIL's house with the story that they were delivering (an unordered) pizza and needed to take my FIL to the bank. My FIL's caregiver - a quite large man - wouldn't let them in or my FIL to the door, and threatened to call 911 if they didn't leave immediately. At that point we knew my FIL could no longer live alone or remain in that house. He was terrified by the incident and agreed. He chose a beautiful nearby assisted living facility where he thrived, found a girlfriend
and was never again bothered by those creeps.
On an aside: A bit into this, a NY postal inspector investigating this fraud ring caught an envelope my FIL had sent to a known scammer address. My FIL's phone number was publicly listed so he called and left a message, which went to my phone. Of course I checked this guy out ten ways from Sunday before talking to him.
He was very illuminating, explaining the nature of the scams, how they first hook people in, slowly suck them dry, then get these now-desperate folks to do some of the ring's monetary collecting and forwarding work for them. Among the victims he'd talked to were doctors, lawyers and psychiatrists.
The unopened envelope containing several hundred dollars in cash was returned to us and required picture ID to get it released.
A couple of years later an unordered pizza came to our house in my FIL's name. The Domino's delivery guy - obviously not part of the scheme - said the order had been called in but no payment made (so no CC info to track). We gave him a tip (this wasn't his fault), briefly explained the situation and declined the pizza. When we called the police the officer said the Jamaicans probably had someone parked nearby, watching to see if we'd accept the pizza or if my FIL appeared.
We were incredibly fortunate. As
@Buckeye attested, many are scammed out of everything they have.
p.s. LAPD's classification for this kind of crime is "defrauded by trickery."