The county, or the State acting through the board, may enter into a written contract with any public body or person providing for the billing and collection by such public body or person of any of the service charges levied by the board. If all or any part of any bill rendered by any such public body or person pursuant to any such contract is not paid, and if that public body or person renders any public utility service to the public body or person billed, that public body or person may discontinue its utility service until the bill is paid. The contract between the board and such public body or person may provide for such discontinuance.