Whenever notice of any loss or damage has been given to the insurer or its agent, the insurer shall, upon written request, deliver to the insured or to the person to whom the benefits are payable the forms for such preliminary proof of loss or damage as may be required under the policy. Such forms shall be delivered within fifteen days after written request has been made or mailed to the insurer by the insured or person to whom benefits are payable. The failure or refusal of an insurer or its agent to deliver such forms within fifteen days of written request shall be deemed a waiver of any condition, stipulation or provision in the policy requiring preliminary proof.