In all cases where money has been paid since the passage of the act of March 20, 1889, on account of the purchase price of lands where the certificates or applications, became invalidated by reason of that act, the amount to be repaid as shown in the certificate to be issued by the commission in exchange for the certificate of purchase, shall be only such amount as has been paid on account of the purchase price of such lands subsequent to the passage of the act of March 20, 1889.
Ca. Pub. Res. Code § 7972