It will either be with Missouri or Kansas Secretary of State. You won’t have access to an EIN but will be able to search for the business name and see the associated business ID number and point of contact. Often that point of contact is a contracted entity called a registered agent that will simply handle mail and forward to the owners.

*edit* That is assuming the business is registered in that state. If it is registered in WY or DE or some such, then good luck. (If it is even a real business. Who knows?)