Section 15. A treasurer of a savings bank, national bank, trust company, co-operative bank, benefit association, insurance company or safe deposit company authorized to do business in the commonwealth who, upon written request, signed by an officer of the department, unreasonably refuses to inform him of the amount deposited in the corporation or association to the credit of a person named in such request as a charge upon the commonwealth, or as an applicant to the commonwealth for public assistance under chapters one hundred and seventeen, one hundred and eighteen, or who wilfully renders false information in reply to such request, shall forfeit five hundred dollars to the use of the commonwealth. Upon such request, a treasurer, as aforesaid shall furnish the records on deposits and withdrawals during the past five years, concerning any applicant for or recipient of public assistance under chapters one hundred and seventeen, one hundred and eighteen, to any officer of the department.