(1) Personal service of a notice or summons by or order of the Authority shall be made by delivering the notice or summons or, in the case of an order, a sealed copy thereof to the person on whom service is directed. The service shall be proved by affidavit.
(2) Where personal service cannot be made, or is shown to be not reasonably practicable, the Authority may order such substituted service as it may deem sufficient in the circumstances of the particular case.