we can not see your return or the letter. is the letter legit?
if you paid for Audit Defense, you should contact them if not for a fee you can contact them to look into the matter
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.
if you don't have AD and do not want to pay for their services you can call the IRS
Rather than calling the number in the letter which will be fake if the letter is not legit, call 800-829-1040
First choose your language.
Then 2
Then 1
Then 3
Then 2
You should then be transferred to an agent, but could be put on hold. The agent will be able to tell you if the letter is legit and if so, what the IRS changed.
another way to check would be to go to irs website
https://www.irs.gov/
and use view your account or get your tax record which will have a transcript of your return. the transcript will show on some lines what was reported and right below that a line ending with "per computer" - what the IRS says is correct
