he IRS will not: Call you to demand immediate payment. The IRS will not call you if you owe taxes without first sending you a bill in the mail.
IRS will not:
Demand that you pay taxes and not allow you to question or appeal the amount you owe.
Require that you pay your taxes a certain way. For instance, require that you pay with a prepaid debit card.
Ask for your credit or debit card numbers over the phone.
Threaten to bring in police or other agencies to arrest you for not paying. (If you don’t owe taxes, or have no reason to think that you do: Do not give out any information. Hang up immediately.)
What you can do:
If you think the call is a scam you can contact TIGTA to report the call. Use their “IRS Impersonation Scam Reporting” web page. You can also call 800-366-4484.
Report it to the Federal Trade Commission. Use the “FTC Complaint Assistant” on FTC.gov. Please add "IRS Telephone Scam" in the notes.