(a) Notification of quota restrictions. If because of quota restrictions, a mail importation cannot be released, the director of the port of destination shall notify the addressee on Customs Form 3509 of the procedure required by paragraph (b) of this section, and shall inform the addressee that upon return of the Acknowledgement of Delivery by Postal Service, the packages admissible under the absolute quota will be forwarded to him and the restricted packages will be returned to the sender as inadmissible. The port director may at his discretion hold packages if it appears that the absolute quota will reopen in less than 30 days.

(b) Acknowledgement of delivery. An Acknowledgement of Delivery by Postal Service shall be sent to the addressee. He shall be advised that if he desires to secure release of less than the total number of packages of the merchandise, the Acknowledgement of Delivery by Postal Service must be signed by him and returned to the port director. Such Acknowledgment of Delivery by Postal Service shall be in the following form:

(c) Agreement to less than full delivery. If, in any case, the sender of a mail package has indicated his agreement to the delivery of less than the entire importation at one time, an Acknowledgment of Delivery by Postal Service need not be secured from the addressee.

(d) Deposit required. If a portion of a mail shipment may be released, the port director may require a deposit of an amount sufficient to defray the expenses of repacking merchandise for shipment by mail to the addressee. The shipment shall be under Government frank without new postage.