In the case of liquidation or dissolution of the telephone bank, after the payment or retirement, as the case may be, first, of all liabilities; second, of all class A stock at par; third, of all class B stock at par; fourth, of all class C stock at par; then any surpluses and contingency reserves existing on the effective date of liquidation or dissolution of the telephone bank shall be paid to the holders of class A and class B stock issued and outstanding before the effective date of such liquidation or dissolution, pro rata.