Have you checked your own bank accounts to look for deposits of $1400 per person sometime after mid-March of 2021? If you received letter 6475 from the IRS that says you got those checks and you say on your return that you did not receive them it will put $1400 per person into your refund by giving you the recovery rebate credit on line 30.
The IRS will cross check, see that their records show that they sent you the $1400 per person already, and they will reduce your refund.
Do make every effort to answer the question correctly when you are in the recovery rebate credit section.