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.
IRS international customer service phone numbers and address: 1  International Taxpayer Service Call Center Phone Number: 267-941-1000. 2  Austin Customer Service Number: 512-416-7750 (not toll-free). 3  Puerto Rico IRS toll free Number: 1-800-829-1040. 4  Virgin Islands Customer Care Number: 1-800-829-1040.