You can view your account on the IRS web site:
https://www.irs.gov/payments/view-your-tax-account
The information you can view on your account also includes ways to pay, including how to set up a payment plan if needed.
It is very difficult to call the IRS at this time.
To call the IRS:IRS: 800-829-1040 hours 7 AM - 7 PM local time Mon-Fri
Listen to each menu before making the selection.
First choose your language. Press 1 for English.
Then do NOT choose the first choice re: "Refund", or it will send you to an automated phone line.
Instead, press 2 for "personal income tax".
Then press 1 for "form, tax history, or payment".
Then press 3 "for all other questions."
Then press 2 "for all other questions." It should then transfer you to an agent.
If you have prior year balance dues (that you are not disputing ) then file the 2020 return asap so the refund can be used to pay off or down that debt ... the longer you wait the more it costs you in penalties and interest.
can you provide more information. it would be highly unusual that you would be hearing from the IRS for the first time for taxes you owe from the years you cite. if you got previous notices which you ignored you may not have any recourse.
if you want help
The Audit Defense service is provided by TaxResources, Inc., also called TaxAudit.com, in partnership with TurboTax. If you paid for Audit Defense and you received an IRS notice, call TaxResources, Inc. at 877-829-9695, or report your IRS notice on their web site at http://intuit.taxaudit.com/. Do not contact the IRS until you have spoken to TaxResources. They may contact the IRS on your behalf