Irs audited me saying I don't qualify for HOH and EIC when the rules say I do. the mother claimed same dependent but for the child tax credit which is different

according to turbo tax I qualify for HOH by income and filing single

also turbo tax notified me of another discount for EIC because of a qualifying dependent/child is living in my household for more than half the year  (7months)with me providing all cost.

I did not apply for child tax credit because the mother claimed her for that. it even asked me if the other main parent was  claiming the dependent for Child tax credit I said put yes

what do I do