The Recovery Rebate Credit (Line 30 of your 1040) is included in your federal tax refund. The Recovery Rebate Credit is for taxpayers that did not get a third stimulus payment. The IRS likely has on file that you did receive a third stimulus payment and therefore, deducted the credit from your refund.
If you did not receive the third stimulus payment and the IRS has on file that you did, then you should start a payment trace.
To start a payment trace:
