Ameren Services Company Info About the Company Invester-owned electric and natural gas utility serving Missouri and Illinois. Assist with confidential business location services. Address Ameren Services P.O. Box 66149, (MC 250), St. Louis, MO 63166-6149 United States Contact Website: ameren.com Phone: (800) 981-9409 Request More Information Name * Your Email * Message What code is in the image? * Enter the characters shown in the image.