File a police report for theft of funds.

Notify the IRS, state, credit bureaus, etc.  re Identity Theft as well.

If any of this was done through the mail, also file a report with the Postal Inspector.

The police won't do anything.

You can report fraudulent Tax Returns to the IRS on a form they supply for that purpose.

The only way to get your money is to file a correct return for yourself on paper. IRS will investigate the conflict.