Cal. Fin. Code § 18425.3

If the liquidator doubts the validity of any claim, the liquidator may reject the claim and serve notice of rejection upon the claimant either by certified mail or personally. A notice of rejection given by mail, addressed to the claimant at the address set forth in the claim, shall constitute sufficient notice of the rejection. Any action upon a claim so rejected must be brought within 30 days after the mailing of the notice or personal service of the notice in the court in which the liquidation proceeding is pending for an order to show cause why the claim should not be allowed. Failure to bring such action within 30 days to enforce the payment of or establish any rejected claim shall forever bar any such action.