About Aphthous Ulcer: These small sensitive painful craters in the mouth are common canker sores. There are many possible causes of apthous ulcers and frequently the cause is unknown. See also: sub-topics
The IRS phone number for individuals is (800) 829-1040. Businesses can call (800) 829-4933. Hearing impaired individuals can contact the IRS using TDD at (800) 829-4059. Operating hours are between 7 a.m. and 10 p.m. in your local time zone. After hours, a recording will direct you. Have all your paperwork in front of you when you call.
Contact Info. Phone Contact Numbers. Customer service hours are from 7 A.M. to 10 P.M. EST Monday to Friday and 8 A.M. to 5 P.M. EST Saturday and Sunday. IRA customer service is open from 8 A.M. to 6 P.M. EST Monday to Friday and 8:30 A.M. to 4:45 P.M. EST Saturday and Sunday. Customer Service: 1-888-762-2265.