Same issue with me, I called the IRS and waited on hold for about 30 minutes, I told them that me and husband both made well under the threshold both years for 2019 and 2020 but we only got half what I understood was owed to us, we got back $2,800 rather than the $5,600 for a family of 4. both our children were on both 2019 and 2020 as dependents and both are under the age of 6. the IRS basically told me they had no information on how to handle payments that are short and to keep checking the website for updates. I honestly think it is a glitch in system.
