Did you also file a tax return claiming your children as dependents? If so, did you receive a letter from the IRS requesting you to amend your tax return if your filed return was incorrect?
Or are you just asking what to do if someone filed a return improperly claiming you and your children?
You can report a fraudulent tax return using the information from this IRS website - https://www.irs.gov/individuals/how-do-you-report-suspected-tax-fraud-activity
