Billing and collection practices of electric service providers. Each person selling generation, transmission, distribution, metering, or billing of electric service shall display the name, the toll-free telephone number of such service provider, and a description of the services provided on all bills submitted to subscribers of such services. All personal information relating to the subscriber of generation, transmission, distribution, metering, or billing of electric service shall be maintained by the service providers solely for the purpose of generating the bill for such services, and shall not be divulged to any other persons with the exception of credit bureaus, collection agencies, and persons licensed to market electric service in the State of Illinois, without the written consent of the subscriber.