Do you agree with what the IRS describes in their notice to you? What exactly did the IRS change on your return?
As far as paying taxes, you pay the taxes owed if the IRS is correct. User entry of incorrect information or the failure to provide all the tax data is the user's responsibility. If you pay an IRS or state penalty or interest because of a TurboTax calculation error then TurboTax will pay the penalty and interest under the 100% Accurate Calculations Guarantee.
For assistance with the IRS notice you received go to this TurboTax website for Audit Support - https://support.turbotax.intuit.com/irs-notice/audit-support/
See this TurboTax support FAQ for the Accuracy Guarantee - https://ttlc.intuit.com/questions/1901269-how-do-i-submit-a-claim-under-the-turbotax-100-accurate-ca...
And this Support FAQ on what is needed to file a claim - https://ttlc.intuit.com/questions/1901060-what-documents-do-i-need-to-submit-a-claim-under-the-turbo...
