23 CAR § 466-1305. Overbilling and underbilling

(a) Where a TP has overbilled a customer, the TP shall make a refund or billing credit in a subsequent billing cycle following discovery and computation of the overbilled amount. (b) When a TP bills a customer an amount correcting a previous underbilling and it results in an undue hardship on a customer, the customer may call and make special payment arrangements unless the underbilling was caused by unauthorized or fraudulent use or procurement of service.