Hi rinnmoto,
I hope the following article helps.
Understanding Your Letter 4800C
https://www.irs.gov/individuals/understanding-your-letter-4800c
If you purchase Audit Defense for tax year 2020, kindly contact (877) 829-9695 for further assistance.
If you did not purchase Audit Defense, and disagree with the proposed IRS changes, please reply to IRS with supporting documents.
TurboTax customer service
https://ttlc.intuit.com/turbotax-support/en-us/help-article/account-management/turbotax-phone-number...
Hope the above helps.
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