Hello and welcome. My name is ***** ***** it will be my pleasure to assist you. Please just give me a moment to review your question....
This is a scam. The IRS does not call people to tell them they are going to be sued. First, the IRS would not attempt to sue you until after they had conducted an audit of your taxes, which would require them to meet you in person and go over your taxes face-to-face. Second, if the IRS was going to sue you they wouldn't threaten it, they would simply do it. Finally, the phone number from which you were called is CONFIRMED as being the number of a scammer. The number has no affiliation whatsoever with the IRS.
So, you simply must cut off all communication with this person and ignore all future phone calls from them or anyone else claiming to be "law enforcement" or the "IRS" regarding this matter.
I hope that you find this information helpful. Please do not hesitate to let me know if you have any questions or concerns regarding the above and I will be more than happy to assist you further.
If you do not require any further assistance, please be so kind as to provide a positive rating of my service so that I may receive credit for assisting you. Very best wishes moving forward.