§ 118. Payment to an authorized payment agency. 1. In any case where a
public utility company or municipality rendering equivalent utility
services permits its customers to pay their bills to a payment agency
authorized by the corporation or the municipality for collection of
bills, the date of payment to such authorized payment agency shall be
the effective date of payment of such bill, and the payment shall be
regarded as if it were paid directly to the corporation or municipality
on such date. Where a customer of such corporation or municipality has
paid a bill to an authorized payment agency on or before a designated
due date, no penalty or extra charge shall accrue on such bill for the
reason that the payment did not reach the corporation or municipality on
or before the designated due date. Notwithstanding the provision of this
section, payments to authorized payment agencies by residential
customers shall be governed by article two of this chapter.

2. Backbilling. Except as provided for residential utility service
pursuant to article two of this chapter, no public utility company or
municipality may render a bill for previously unbilled service, or
adjust upward a bill previously rendered, to a residential customer
after the expiration of twenty-four months from the time service to
which the bill or adjustment pertains was provided. This provision shall
not apply when the culpable conduct of a customer caused or contributed
to the failure of the company or municipality to have rendered timely or
accurate billing.

3. Credit or refund of overpayments. (a) The commission shall have the
power to require a public utility company or municipality to provide a
refund or credit to a customer when a payment has been made in excess of
the correct charge for actural service rendered to the customer.

(b) If a residential customer becomes eligible for a lower rate
because he or she changes the character of the service received and if
excess payment resulted from the failure of the customer to notify the
utility or municipality providing service of a change in the character
of service received or from the failure of the utility or municipality
to change the rate after such notification by the customer, such a
customer will be entitled to such lower rate from the date the change
occurs but such a customer shall not be entitled to such lower rate for
more than twenty-four months prior to the giving of actual notice to the
utility or municipality providing service.