One time I got that call and when I them 'you're not from the IRS, this is a scam and I'm not going to be a victim today' they started swearing at me with words I cannot repeat. The latest here is getting a solitation call where they ask 'Can you hear me okay?' They record you when you say yes then use that recording to say you have agreed to purchase whatever item they are selling. A couple cases have made it to court and the victim lost as the scammer had a recording of them saying 'yes'.