(a) Any person who by reason of ignorance, forgetfulness, or misunderstanding improperly or unlawfully uses official mail shall be liable to the District for double the cost of the postage.
(b) Any person who willfully violates provisions of this chapter shall be subject to a fine not exceeding $1,000 or imprisonment not exceeding 1 year, plus double the amount of money incidental to the unlawful mailing.