§ 51. Violation of this article. The mayor or local licensing authority so licensing such collateral loan broker shall have full power and authority after a hearing to impose fines and penalties of not less than twenty-five dollars nor more than one hundred dollars upon persons offending against any of the foregoing provisions of this article for each and every offense, excepting sections forty and forty-one, and may also suspend or revoke the license of the collateral loan broker willfully violating any of the aforesaid provisions.