I received a call from this number stating that I had a lawsuit pending from the IRS and it was an attempt to collect a debt.  When I called back it was a woman attempting to gather personal information about me.  I asked how I could have a lawsuit and was hung up on twice.  I contacted the IRS.  IRS verified there was no such lawsuit pending on me.

How much time did you waste waiting to hear that? The IRS doesn't randomly call folks, much less threaten lawsuits, arrests, warrants, floggings, beheading, etc.,. you'll be hearing about it in the mail before anything. Don't waste time calling unknown numbers back, either. The motive is to instill fear so you pay a bogus debt, which they'll be happy to settle, often through absurd manner. Bother them back by allowing no kind of answer from unknown numbers and letting your phone ring. Without those, these characters can do absolutely nothing while you hear maybe a ringing phone only.