Miscaluclated EITC?

I received a letter from the IRS stating:

 

"We changed the amount claimed as Earned Income Credit on your tax return. The amount claimed as Earned Income Credit was figured or entered incorrectly on your tax return.

 

The Earned Income Credit is figured on worksheets in the tax return instructions. By completing the worksheets you compute a dollar amount that you use to find the amount of your Earned Income Credit from the Earned Income Credit Table. This amount is then entered on your tax return. Review your Earned Income Credit worksheets in your tax return instructions and Schedule EIC. Check for errors in math. Check to see you used the correct column in the Earned Income Credit Table for determining your Earned Income Credit."

 

I bought TurboTax Premier and paid for the Audit Protection, however I've called 3 times already and no one has successfully transferred me to the appropriate department to help me resolve this issue.  Each time I've been "transferred" the phone call has been disconnected.

 

I though there 100% accuracy guarantee? At least that is what is advertised on the website.