You need to put a trace on the stimulus payment the IRS says was sent. Go to this IRS website for how to start a trace - https://www.irs.gov/newsroom/questions-and-answers-about-the-third-economic-impact-payment-topic-j-payment-issued-but-lost-stolen-destroyed-or-not-received
Are you sure-----we keep seeing posts from people who "forgot"they received that $1400 per person. Check your bank records to see if you had any deposits of $1400 per person on your tax return.
If you really did not receive the stimulus payment that the IRS says you received:
LOST THIRD STIMULUS CHECK
That would be your call.
If you are getting a refund WITHOUT the recovery rebate, you might want to claim what the IRS says you received in order to get your return processed. You may then file an amended return afterwards to get the missing economic payment.
If you are not due a refund and are sure you did not get the payment, you could file your return that way, but the IRS will hold up processing since it won't match their records.
If you did not get the payment, and the IRS indicates that it was sent, check your bank records to see if it was direct deposited.
If you still cannot find record of the payment, request a trace be done by the IRS.
If the IRS can find and stop payment on it, you can apply for the payment again by filing an amended 2021 tax year return.
You may need to file Form 3911 to request a trace be done on the payment.