Mother withholding our children's social security number

[IndubitablyFoolish]

So in 2021, the mother of our children stopped working in June. Up until that point, we split the cost of rent and bills. Afterwards, I covered all the expenses for the rest of the year. We have lived together for 15 years, although the lease and bills are in her name. When I asked for the children's social security number to fill out my taxes, she has refused to give me the information. I'm left under the impression she has already claimed the children as dependents on her taxes. What can I do about this situation?

[SweetieJean]

As their legal father, you can go to the Social Security office and get their SSN's.  But you will have to file your tax return by mail, and the IRS will sort it out.

[IndubitablyFoolish]

How? I'll need forms of documentation to provide that they're my children. Such as birth certificate, medical records, immunization records, etc. Which she has and won't allow me access to.

[SweetieJean]

Call the SSA office on Monday and ask them the best way to proceed.  You can get their birth certificates from the government.  But it sounds like you may need to see a local attorney.