For specific questions related to your tax return or Free File Fillable Forms, contact the IRS. Contact information is available at this IRS support page, which also includes a form to e-mail the Help Desk (the most effective way to resolve your issue).
If you are using brand name software from a Free File Alliance member company, please contact your chosen software provider with questions. (Note: All Free File Alliance members list customer service contact information on their web pages.)
Free File program-related inquiries:
14098A Lee Highway
Centreville, VA 20120
P.O. Box 893
Centreville, VA 20122