Subject to the provisions of section 1911 of this title all contracts or policies of insurance heretofore or hereafter issued, reinstated, or converted shall be incontestable from the date of issue, reinstatement, or conversion except for fraud, nonpayment of premium, or on the ground that the applicant was not a member of the military or naval forces of the United States. However, 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.