New "IRS Lawsuit" scam number.  Left voicemail saying IRS was filing a lawsuit--a scam that's been around for several years now.  Don't talk to them, don't call them back.  See https://www.treasury.gov/tigta/contact_report_scam.shtml , especially if you gave them any info or sent any money.  You can also file a complaint with the Federal Trade Commission. Add "IRS Telephone Scam" to the comments in your complaint