Early in the 2020 tax season some returns had the stimulus payment added and it was up to the user to remove those payments if they had already received their payments.
If a return was filed with a recovery rebate added to the refund, the IRS checked by hand to be sure that the stimulus had not been paid to the person requesting it. If that person already received the stimulus, the IRS sends a letter to inform that the payment is not owed.
Check to be sure you received both your first and second stimulus payment. If you did not receive them and the IRS says that you did, they will have to trace what happened to the payments.
