Those are generic reasons why they adjusted the Recovery Rebate Credit on your return. A common adjustment is if you claimed the Recovery Rebate Credit on 1040 line 30 when you already got the 3rd Stimulus payment or reported the wrong amounts. Do you have an amount on line 30? The IRS knows they already sent it to you. Line 30 is only if you didn't get the full amount or qualify more.
If you claimed a missing stimulus payment on your return but the IRS took it off you have to ask the IRS. They think they already sent it to you. 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.
Request a trace for a missing third Stimulus payment
https://www.irs.gov/newsroom/questions-and-answers-about-the-third-economic-impact-payment-topic-j-p...
