If your refund was reduced to pay a past due tax obligation with the IRS, call 1-800-829-1040 to obtain more information. The IRS will send you a notice of the offset in 6-8 weeks after filing the return.
If your Federal Refund was applied to a past due debt with another government agency such as Child Support, Student Loans, Medical Bills, etc call 1-800-304-3107. This number is automated and will tell you who took your refund.
If you are having problems resolving an issue with the IRS, the Taxpayer Advocacy Group is there to help you with a variety of tax matters that you have been unable to resolve with the IRS. Call them at 1-877-777-4778