It's a scam.
It's not the IRS. They are lying and committing fraud. I think they're outside the country, though.
It's a bunch of Indian-based scam artists trying to get you to buy pre-paid credit cards, with which you will supposedly pay back the IRS.
Do not fall for it.
DO, however, waste their time as much as possible.
Keep them talking.
Tell them you need more information.
Tell them you still need more data.
Don't pay for anything.
Don't give them a credit card.
THEY ARE NOT the IRS.
I just received a very spooky call from this number. I did not answer, they left a voice message. It started off as a whispering like a practice of what he was going to say, then the man with a deep Middle Eastern (Indian) Accent said he was calling from the Department of the IRS regarding a "case" against me and if I didn't call back in the next few hours I would be the sole proprietor to legal action being taken against me. I knew it had to of been a scam, it's easy enough to spoof numbers to come up on Caller ID noting "Washington DC", anyone can do it nowadays.. it is totally illegal and I hope whomever is behind making these calls gets caught. They could at least learn to speak English better, or hire someone that speaks English with no accent to try and scam people, I highly doubt the IRS or any Government bureau or department has Middle Easterners making threats to people over the phone about "cases" which he left no further information about.