If you suspect a scammer called you, always keep them on the line as long as possible. Feed into the scam and act as gullible as possible, give them fake cc numbers, etc.
Best to extract as much iinfo as possible, business name, callback numbers, email addresses, etc. The more info, the easier it is for the FCC to bring enforcement action against fraudulent callers.
haha, "four-flag key" is still an inside joke with my family because of how many times we got a scammer to say it while they "provided tech support" to us :)