I don't mess with the telemarketers, don't do business with them, but try not to be rude, but the scammers are fair game.
Running linux when a person calls, preporting to be from Windows. Apparently, my computer had an 'error' and i needed to run a number of commands to fix it. Asked what the error was and given a non-answer. We went thru the usual, ignorance on my end, exasperation on his end before he figured to ask me what OS i was running. I started a conversation with him while typing MS OS commands on my linux machine, asking about his education, how his parents were, then what did he think his mother would think about stealing from others. He tried to say he was not stealing, but i argued that i didn't have the OS his so called 'error' would indicate and that he wasn't providing a service, but actually trying to exploit someones ignorance. He finally confessed and said his mother would be very angry with him and said he was sorry and bid be well before saying good bye.