Section 106. If a greater rate of interest or amount for expenses than is allowed under sections ninety-six to one hundred and eleven, inclusive, has been paid on any loan to which said sections apply, the person who paid it may file a complaint with the commissioner, who may, after a hearing, order such excess amounts refunded, or may make such other order as he may deem necessary. The filing of the complaint and the decision of the commissioner shall not affect the right of the complainant under section one hundred and three, who may, in an action of contract or suit in equity, recover back the amount of the unlawful interest or expenses, with twice the legal costs, if such action or suit is brought within two years after the time of payment.