If your refund was less than you expected, it may have been reduced by the IRS or a Financial Management Service (FMS) to pay past-due child support, federal agency nontax debts, state income tax obligations, or unemployment compensation debts owed to a state.
If your debt was submitted for offset by another agency, FMS will take as much of your refund as needed to pay off the debt. The remainder (if any) will be issued to you by check or direct deposit.
Normally the IRS sends a letter within two weeks of the issuance of a check or direct deposit. The letter will detail the amount of the offset and the amount you’ll receive after the offset. You can check the IRS Where's My Refund page, or call 1-800-829-1040.
Contact the agency with which you have a debt or call FMS at 1-800-304-3107.