(a) In its utility operations, a public service company may not: (1) sell, render services, or furnish a commodity until the public service company files and publishes its rate schedules in accordance with § 4–202 of this title; or (2) demand or collect: (i) compensation that differs from compensation specified in its rate schedules that are in force at the time of the demand or collection; or (ii) a charge that violates this division. (b) A person may not assist, allow, or attempt to assist or allow the actions prohibited under this section by any means, including false billing, false classification, false weighing, or false report of weight, even if a public service company or its personnel consents to or connives with the prohibited action.
Maryland Legal Code