In an action against an unauthorized insurer upon a contract of insurance issued or delivered to a person in this State, if the insurer has failed for thirty days after demand prior to the commencement of the action to make payment in accordance with the terms of the contract, and it appears to the court that the refusal was vexatious and without reasonable cause, the court may allow to the plaintiff reasonable attorney’s fees and include the fees in any judgment that may be rendered in the action. The fee shall not exceed twelve and one-half per cent of the amount that the court or jury finds the plaintiff is entitled to recover against the insurer, but in no event shall the fee be less than $25. 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.