Every life insurance company doing business in this state shall return with, and as part of any policy issued by it, to any person taking such policy, a complete copy of each application or other document held by it which is intended in any manner to affect the force or validity of such policy. A company which neglects to do so is estopped from denying the truth of any such application or other document, so long as it is in default for such copy. In case such company neglects for thirty days after demand made therefor, to furnish such copies, it is forever barred from setting up as a defense to any suit on the policy, any incorrectness or want of truth of such application or other document.