Scammers can go die in a fire.
My phone numbers are on the do not call list. I get robocalls all the time; when I pick up these calls I tell them I'm on the do not call list so I know they're low life scammers (to which rather than disconnecting they start cussing me out, proving my accusation to be true) and invite them to consume copious amounts of strychnine, because suicide is far more honorable than being a fucking scammer and they'll be doing humanity a favor. Alternatively I'll play along and then after a bit I tell them I know they're scammers and while I've kept them tied up in a conversation I've kept them from scamming suckers. Another approach is to read Trumpster/Deplorable racist rants (based on their accent) I have bookmarked, hoping to demoralize them. Blocking their numbers doesn't work due to CID spoofing.
CID spoofing has become a big problem because it's trivially easy (in fact you can do it on most (all?) smartphones). I occasionally get calls from people claiming I called them marketing crap, so obviously someone used my phone # in their CID spoofing. No, I didn't call them. I tell them about caller ID spoofing and how it works but they are usually unconvinced. I end up blocking their numbers so I don't get repeated calls from people who choose to remain aggressively stupid.