No I did not misunderstand you ... the 2019 is immaterial now. The ADVANCE payments were not sent because you were a dependent on the 2019 return so to get the missing payments you must now file a 2020 return and do not indicate you were being claimed as a dependent on someone else's return. If you filed the 2020 return and the IRS denied you the credit then only they can explain why. How long the IRS will take to review the info you sent in already is a mystery however the excuse that you were claimed as a dependent in 2019 doesn't hold water.
