We cannot see the notice ... read it thru carefully to see what it says exactly. Only when you know what happened can you plan your next steps if any.
Double check your bank statements and Check your IRS account (both accounts if married) to see how much you did get for the stimulus payment advance ...
Your Online Account | Internal Revenue Service
If the IRS thinks they sent it to you but you didn't get 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...
