Rule 439. A complaint must be limited to matters involving alleged unjust, inaccurate, or improper rates or charges or unlawful or unreasonable acts, practices, or omissions of a utility, including a violation of any commission rule, regulation, tariff filed or published by a utility, order, or a violation of a statute administered or enforced by the commission. A complaint may be either formal or informal and may be made by a person having an interest in the subject matter of the complaint or may be made by the commission on its own motion or by staff, subject to applicable statutory standards.
Mich. Admin. Code R. 792.10439