Dependent Question

My fiancé and I have 4 children they all have my last name. He claims 2 of them and I claim 2. My question is they audited him one year and said we needed to turn in school records showing that he lives with me. We turned in the necessary paperwork and they still said he owes for the dependent care credit that they paid him. How can we fix it to where he claims 2 and I claim 2 of the children and be ok?