We do not know what you mean when you say you are "missing" stimulus payments. The federal stimulus payments were issued for tax years 2020 and 2021.
The deadline for the 2020 recovery rebate credit was more than a year ago.
And...the deadline to seek the recovery rebate credit for the 2021 stimulus money was April 15, 2025, so it is now too late.
You can check your online account with the IRS to see which stimulus payments --- if any --- were issued to you.
https://www.irs.gov/payments/your-online-account