What Stimulus payment didn't you get? There have been 3. 1,200 and 600 and 1,400. Did you have an amount on 1040 line 30 for the Recovery rebate credit? That should be if you didn't get the full first 2 Stimulus payments or qualify for more. Has the IRS finished processing your 2020 return? Maybe they haven't sent the refund yet.
The new 3rd $1,400 Stimulus payment will be on your 2021 return next year.
