Auto recording saying IRS and this is my final notice, believe it's a scam because I've not gotten anything in mail

I got this call and it sad case file number and to call back to their business office.

The 1st time I answeted it, some foreign guy(I couldn't understand said the IRS was sueing me for back taxes. Told him i was on fixed income & don't have to pay taxes. He says for me NOT to lie to him. I started to get angry but thought bettrr of it n jus hung up. They left a message on my phone just alil bit ago. Tried callin the # n it saod couldnt be completed as dialed. I would like to know if this is a scam like i think it is. Does anyonr kmow 4sire it is or isn't?