Yes. Where a Disco is shown to have over charged a customer, the Disco has the professional responsibility to write to the customer informing him of the error within 5 working days of being aware of the error. The Disco shall as well proceed to repay the amount to the customer in accordance with the customer’s instruction which must be reasonable. Where no reasonable instruction is received, the amount overcharged will be credited to the customer’s next bill. Regulation 9(7) NERC’s Meter Reading, Cash Collection and Credit Management for Electricity Supply Regulation.