; (B) revoked if the Secretary finds that the permittee has not engaged in the operations authorized by the permit for a period of more than 2 years; or (C) annulled if the Secretary finds that the permit was procured through fraud, or misrepresentation, or concealment of material fact. (2) Order to state basis for order The order shall state the findings which are the basis for the order. (f) Service of orders Each order of the Secretary with respect to any denial of application, suspension, revocation, annulment, or other proceedings, shall be served— (1) in person by any officer or employee of the Secretary designated by him or any internal revenue or customs officer authorized by the Secretary for the purpose