I just had this call and I blocked my number and called back and all I got was a busy signal. The recording said "this is the IRS and this is our last attempt to inform you that there's a case being filed against you." That's stupid cuz the IRS is famous for sending out there lovely letters not recordings. And secondly I know that I am caught up with my taxes so that call was fake.
This is a SCAM. The IRS will never call you for information. You will never be called to inform you about a lawsuit. You will be served in person. Do NOT give them any information.
Informational post:
Your statement is very similar to some of the FAQs in the list of Fatuously Asked Questions (FAQs) asked here.
The answers to those more or less inane questions or statements are summarized at
http://phonehelp.2truth.com/faqs.html
Remember to return here, to 800notes.com, after visiting that site.