When any company under any insurance policy requires a written proof of loss after notice of such loss has been given by the insured or beneficiary, the company or its representative shall furnish a blank to be used for that purpose.  If such forms are not so furnished within 15 days after the receipt of such notice the claimant shall be deemed to have complied with the requirements of this policy as to proof of loss, upon submitting within the time fixed in the policy for filing proofs of loss, written proof covering the occurrence, character, and extent of the loss for which claim is made. (1945, c. 377.)