In any action against an unauthorized foreign or alien insurer upon a contract of insurance issued or delivered in this State to a resident thereof or to a corporation authorized to do business therein, if the insurer has failed for 30 days after demand prior to the commencement of the action to make payment in accordance with the terms of the contract, and the court finds that such refusal was vexatious and without reasonable cause, the court may allow to the plaintiff a reasonable attorney's fee and include such fee in any judgment that may be rendered in such action. Failure of an insurer to defend any such action shall be deemed prima facie evidence that its failure to make payment was vexatious and without reasonable cause. (Added 1967, No. 344 (Adj. Sess.), § 1 (ch. 1, subch. 3, § 10).)