if you ask them lots of questions then tell them how the scam works they start swearing at you and threatening to 'send some men round'.
Send as many as you like, you'll find their bodies by the backdoor, stacked like cordwood.
Yeah, that might be a bit extreme, but, I get angry when I'm getting scammed. They've called here I don't know how many times. If it's the Indian folks (several have been perfectly Merkin-sounding folk), I get a little racist on they asses. As soon as I recognize what the call is, I interrupt with "Tenk yoo, come again.", and hang up. I really hope it upsets them enough that it ruins their entire day.