Please click this IRS link for information on how to report fraud:
https://www.irs.gov/individuals/how-do-you-report-suspected-tax-fraud-activity
If your return was rejected because someone else already claimed your child, you will need to mail your tax returns this year. Once the IRS receives your return, they will send out paperwork to both you and the other person who claimed your child to determine who should be claiming him/her. Once you prove you are the rightful claimer, they will issue the refund to you and rescind it from him.
