During postponement of payments the bank shall remain open for business and be in charge of its officers, but shall not make any loans, investments or expenditures except such as the director will approve as necessary to conserve its assets and pay the cost of operation. The bank's failure during a period of postponement to repay deposits existing at the commencement of the period, shall not authorize or require the director to take charge of or liquidate the bank, nor constitute ground for the appointment of a receiver.