Each utility shall investigate and keep a record of complaints received by it from its customers in regard to safety, service, or rates, and the operation of its system. The record shall show the name and address of the complainant, the date and nature of the complaint, and its disposition and the date thereof. A summary of this record for the previous calendar year shall be sent to the commission by April 1 of each year. Each utility also shall document all contacts and actions relative to deferred payment arrangements and disputes.
Wis. Admin. Code Public Service Commission PSC 134.17