If they filed 2019 and 2020 and got the 2020 EIPS amounts then Id bet money they got the 1400 as well...every single one of my clients that thought they didnt get it, found the amount in their bank account back in March of 2021.

Those that insist they didnt get it when theres no reason they shoudnt have, Ive been leaving it off the return (marking that the DID get it) and filing Form 3911 to trace the payment.