My ex husband claimed one of my sons and isn't suppose. my son lives with me and his dad pays 0$ for child support

[BethanyJ · Accepted solution]

If you try to file and claim the same child that your ex-husband claimed, your federal return will get rejected because your son's SSN has already been used to file for the year.

That being said, only the IRS will be able to get that sorted out for you. The number for the IRS is 800-829-1040.