I got the call from this number, I did not answer on time so I called back. A woman answered as an IRS rep.  She named herself as Alice Morgan and asked if I had received the IRS letter and the case number. Since I did not she was very helpful, too helpful locating me, asking my address and the spelling of my name, which I gave her. She then started the BS, in my case it was that "IRS has filed a suit on me", she mentioned it was either because of a mistake or a voluntary underpayment on my part, and asked me which it was.  The disputed amount was $9850... So at that time I was certain it was a scam, since I do not cheat, and definitely not with the IRS.  I started laughing and I told her that her scam did not work and I hung up. I must say it was well done, even with the background noise of busy offices...