In this billing dispute between a municipal electric service and an industrial customer, the Commonwealth Court was asked to determine whether the Borough was permitted to “back-bill” customers following the discovery of significant under-billing, and whether the Borough could impose a municipal lien for the amount owed. In affirming the determination of the Court of Common Pleas of Lawrence County, the Commonwealth Court concluded that no back-billing was permitted pursuant to the municipality’s applicable ordinance, and that such a contractual agreement was not a proper basis for a municipal lien.