28. Nothing in these Regulations, for the protection of the Treasury or the Director of Savings in respect of any act done or any money paid shall operate to prevent the recovery by any person or his representatives of any money lawfully due to him from the person to whom that money was paid by or under the direction of the Director of Savings, or from the representatives of that person, or affect the right which any person or his representatives may have under an agreement or in respect of a certificate against a third party.