Written notice of demand shall be served on the student or institution indicating the amount owed, reasons owed and method of recovery. The student or institution has 15 days to serve a written response on the corporation indicating agreement with the notice of demand or that it is being disputed and the grounds therefor. If the notice of demand is disputed, the student or institution may submit documentation with the response supporting his claim. The corporation shall act on a claim disputing a notice of demand within 20 days of service of a response and accompanying documentation. With respect to students such action by the corporation shall be considered final agency action. If circumstances warrant, within the judgment of the president, a hearing may be provided by the corporation to an institution, upon its request, with respect to such action, pursuant to the provisions of Part 2005 of this Chapter. In no event shall a demand for a refund be waived or the amount demanded reduced by the corporation without the approval of the Comptroller of the State of New York.