I filed my tax return for 2020 and never got the EIC or head of household credit I always get. How do I get that fixed?

Did your return include the HOH filing status and the EIC and the IRS changed your calculations?  If so, they will send you a letter explaining the changes.  I wouldn't suggest doing anything until you receive that letter.

How are your two dependents related to you?  An unrelated dependent does not qualify you for either EIC or HoH. 

A common example: your friend and their child may qualify as dependents (if they lived with you all year)  but they are not qualifying persons for EIC or HoH.