It sounds like you already filed your income tax return and indicated that you did not receive the 2nd stimulus payment. As such, you were entitled to the Recovery Rebate Credit and received a refund. But it sounds like you later received the check for your 2nd stimulus payment so you tried to adjust your return that you already filed.
If that is correct, you cannot make the changed in the tax return in TurboTax as the return was already filed and accepted by the IRS. Therefore, you account will show $0 within TurboTax as the return has already been sent off and processed. Your Social Security would also be rejected since your return was already electronically filed using your number and can only be used one time per year.
However, since you did receive the 2nd stimulus, you will be notified by the IRS for any changes in your tax return. There may be a delay in processing your return while the IRS reconciles the amounts. You do not need to file an amended return. Please see the link below for additional information.
Correcting Recovery Rebate Credits on returns already filed
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