Subject to the provisions of section 1954 of this title all contracts or policies of insurance heretofore or hereafter issued, reinstated, or converted shall be incontestable from the date of issuance, reinstatement, or conversion, except for fraud, nonpayment of premiums, or on the ground that the applicant was not a member of the military or naval forces of the United States. The insured under such contract or policy may, without prejudicing the insured's rights, elect to make claim to the Department or to bring suit under section 1984 of this title on any prior contract or policy, and if found entitled thereto, shall, upon surrender of any subsequent contract or policy, be entitled to payments under the prior contract or policy. In any case in which a contract or policy of insurance is canceled or voided after March 16, 1954, because of fraud, the Secretary shall refund to the insured, if living, or, if deceased, to the person designated as beneficiary (or if none survives, to the estate of the insured) all money, without interest, paid as premiums on such contract or policy for any period subsequent to two years after the date such fraud induced the Secretary to issue, reinstate, or convert such insurance less any dividends, loan, or other payment made to the insured under such contract or policy.