Ark. Code Ann. § 23-4-107: Rate schedules - Greater or lesser rate not to be charged

No public utility shall directly or indirectly, by any device whatsoever, charge, demand, collect, or receive from any person a greater or lesser compensation for any service rendered or to be rendered by the public utility than that prescribed in the schedules of the public utility applicable thereto then filed in the manner provided in this act. Nor shall any person receive or accept any service from a public utility for a compensation greater or lesser than that prescribed in the schedules.