Received two calls from this number about an hour apart on April 22, 2016. There was one message left but it apparently started before my cell started recording as it started, ". . . this case file. Call us back immediately at 302-333-4196 . . ." I think I shall not call them back but I have blocked them instead.

THIS IS AN IRS SCAM CLAIMING THE IRS IS FALLING A LAWSUIT AGAINST ME. Instructions to call back 302-333-4196. I will file complaint with the treasury inspector general as directed for this type of scam.
They called twice today and the automated female voice left messages both times.

This is an IRS scam phone number 302-333-4196.  Do not call back.

I R S is  filing a lawsuit against me.
The number they called from was
302-333-4662. Beware of these jags.