What number do I call if I have a question regarding Illinois Sales tax and login issues?

You can reach the Department of Sales and Use Taxes here:

• Call us at: 1 800 732-8866 or 1 217 782-3336
• Call TDD: 1 800 544-5304
• Mail your ST-1 forms to: ILLINOIS DEPARTMENT OF REVENUE
  RETAILERS OCCUPATION TAX
  SPRINGFIELD IL 62796-0001
• Mail your ST-1-X forms to: ILLINOIS DEPARTMENT OF REVENUE
  PO BOX 19034
  SPRINGFIELD IL 62794-9034

Website: https://mytax.illinois.gov/_/