After you file
The IRS thinks they already sent it to you. Check your account on the IRS site to see when they sent it ... look under RECORDS ...
https://www.irs.gov/payments/view-your-tax-account
Maybe it went to an account you don't remember. Or you got a check or a card. It was probably easy to miss the debit card in the mail and think it was junk mail. They have to put a trace on it.
How to put a trace on a missing 1st or 2nd Stimulus payment. IRS for Payment Issued but Lost, Stolen, Destroyed or Not Received
See question F3 here, you can expand it to see how to put a trace on it.
