A person who willfully violates this chapter, or who willfully violates a rule or order under this chapter, is guilty of a class B felony and shall upon conviction be fined not more than twenty thousand dollars or imprisoned not more than ten years, or both. However, no person may be imprisoned for the violation of a rule or order if the person proves that he or she had no knowledge of the rule or order. No indictment or information may be returned under this chapter more than five years after the alleged violation.