I received numerous complaints today about this number and their message. NO it is NOT the IRS! You'll get a letter in the mail first and then maybe a knock at your door way before they call you.
Don't answer, don't call them back! The IRS doesn't work this way. When I did owe taxes, they worked things out peaceably with me. This scam call said they are filing lawsuit against me. Yeah they can just try it. ....SCAMM.ERS. ...I feel sad for those who lose out to them. Report them TO the IRS and the FTC :)