It is a IRS scam out of India. Nothing to be worried about. The IRS never calls you and makes threatening calls. There are warnings all over the news about this. If you have elderly friends or relatives,please look out for them and make them aware of these crooks.
I got the same coice recordeing but it was an automated one. Theu claimed to be filing a suit against me. Its a total scam and just blocking the number.