No contract previously made, or later made, by persons engaged in a business or occupation subject to a license or privilege tax, under parts 2-6 of this chapter or any other act, shall be invalid or unenforceable in the courts because of the failure of such persons to have paid such license tax at the time such contract was made or was performed; provided, that such persons shall, prior to the date of adjudication in the court of original jurisdiction, pay double the tax due at the time the contract was made and, in addition, the penalty prescribed by law.