Section 19. A medical service corporation which, upon the death of a subscriber, owes the subscriber’s estate an aggregate sum not exceeding two thousand dollars under any medical service agreement, may, at any time not less than sixty days after the subscriber’s death, pay such sum to the husband, wife and next of kin of the subscriber and any such payment made in good faith shall fully discharge the corporation to the extent thereof; provided, however, that this section shall not apply if, prior to the time of such payment, the corporation has received a written claim under the subscriber’s medical service agreement from any executor, administrator, or special administrator of the subscriber’s estate.