Assuming that you were not a dependent on someone else's tax return and you used TurboTax for both your 2020 and 2021 tax returns -
You were asked in the TurboTax program for tax year 2020 if you received the stimulus payments EIP1 and EIP2 in 2020. If you answered that you did NOT receive those payments then the Recovery Rebate Credit for those payments would have been entered on Line 30 of the Form 1040. The Credit would have been included in the federal tax refund or the Credit would have reduced the amount of federal taxes owed.
You were again asked in the TurboTax program for tax year 2021 if you received the stimulus payment EIP3 in 2021. If you answered that you did NOT receive the EIP3 payment then the Recovery Rebate Credit for the payment would have been entered on Line 30 of the Form 1040. Again, the Credit would have been included in the federal tax refund or the Credit would have reduced the amount of federal taxes owed.
Look at your tax returns for tax year 2020 and 2021 for the credit on Line 30 of the Form 1040.
Go to this IRS website for your tax account to see if the 3rd stimulus payment is entered - https://www.irs.gov/payments/your-online-account
If you are Married Filing Jointly also check your spouse's tax account.
If you checked your bank account in for EIP1 and EIP2 in 2020 and EIP3 in 2021 and the payment from the IRS is not shown then go to this IRS website for how to start a trace on the EIP3 payment - https://www.irs.gov/newsroom/questions-and-answers-about-the-third-economic-impact-payment-topic-j-p...
Go to this IRS website for how to start a trace on the EIP1 and EIP2 payment - https://www.irs.gov/newsroom/2020-recovery-rebate-credit-topic-f-finding-the-first-and-second-econom...
