A person who willfully and intentionally violates any provision of this subtitle is guilty of a misdemeanor and on conviction is subject to a fine not to exceed $500 per violation. For a violation of a provision of this subtitle, a consumer under a rental-purchase agreement may recover from the lessor committing the violation, or may set off by way of a counterclaim in an action brought by the lessor or its assignee, an amount equal to: Actual damages; and $500 plus reasonable attorney’s fees and court costs. A lessor or its assignee may not be held liable under this subtitle if the lessor or its assignee proves by a preponderance of the evidence: That the violation was unintentional and resulted from a bona fide error, notwithstanding the maintenance of procedures reasonably adopted to avoid that type of error; and That the lessor or its assignee corrected the error and refunded any money excessively charged due to the error, within 30 days after discovering or receiving notice of the error.