The 3rd Stimulus payment was 1,400 per person and came out starting in March. The IRS says they sent it to you. Did you get letter 6475? 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.
Check your IRS account to see what they sent you (check both spouse's accounts if married)
Your Online Account | Internal Revenue Service
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...
