Honest and reasonable mistake
21.  A person is not guilty of contempt of court under section 4(1), (2) or (3) if the person satisfies the court that the failure or refusal to comply with a judgment, order, decree, direction, writ or other process of court or any undertaking given to a court was wholly or substantially attributable to an honest and reasonable failure by that person, at the relevant time, to understand an obligation imposed on the person bound by the judgment, order, decree, direction, writ, process or undertaking and that that person ought fairly to be excused.