Any utility doing business in this state or any of its authorized agents, officers or employees who are guilty of knowingly or willfully charging, demanding or receiving any rate or charge for any commodity or service different from that authorized by its lawful tariffs on file with the Alabama Public Service Commission shall be guilty of a misdemeanor and, upon conviction, shall be punished by a fine of not more than $1,000.00 for each offense.
Ala. Code § 37-8-21 (1975)