Businesses can contact the Internal Revenue Service on its Telephone Assistance for Businesses at 800-829-4933. The phone line's hours of operation are Monday to Friday, 7:00 a.m. to 7:00 p.m local time. People who believe they may be a victim of identity theft can call 800-908-4490 for automated and live assistance.  A separate phone number exists for Exempt Organizations, Retirement Plan Administrators, and Government Entities: 877-829-5500. The phone line's hours of operation are Monday to Friday, 8:00 a.m. to 5:00 p.m local time. People with hearing impairments can call 800-829-4059 (TDD). 