see this link but only the IRS and you know what changes were made to your return that might disqualify you
for example if the irs increased your adjusted gross income above a certain amount, you would no longer qualify.
After you file your tax return, TurboTax does not get any information at all from the IRS/state. So nobody at TurboTax knows what the IRS did to change your return and dis-allow the EIC you expected. You should receive a letter of explanation from the IRS. If you receive that letter and do not understand it, tell us what it says and we may be able to help you understand it. Please do not include any personal information.