law: 35. Services of order, notices, etc.-
  Any order passed or notice issued under this Act, shall be served-
  (a) by tendering the order or notice or sending it by registered post to the dealer for whom it is intended or to his agent; or
  (b) if the order or notice cannot be served in the manner provided in clause (a), by affixing it on the outer door or some other conspicuous part of the last known premises of the dealer.