who did you report it to?
if someone used her SSN already to file the tax return, simply complete your tax return as normal and MAIL it in. The IRS will figure it out.
Further, going forward, you may want to get an IRS PIN to preclude anyone else from using her SSN to file.
https://www.irs.gov/identity-theft-fraud-scams/get-an-identity-protection-pin
If someone else already used your dependent's SSN on a tax return, then you cannot e-file your own return that claims them. The only way for you to claim them and file your tax return is by mail. Print it, sign and date the return, and mail it in. The IRS will sort out the duplicate use of the SSN.
When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s. Use a mailing service that will track it, such as UPS or certified mail so you will know the IRS/state received the return.
Federal and state returns must be in separate envelopes and they are mailed to different addresses. Read the mailing instructions that print with your tax return carefully so you mail them to the right addresses.