(4) 36. 37. Costs (1) The costs of and incidental to any proceedings shall be in the discretion of the Tribunal, which may direct that any party against whom an order for costs is made shall pay to any other party a lump sum by way of costs or such proportion of the costs as it may deem just (2) When no order for payment of a lump sum has been made, the Registrar shall, if so required by an party to the proceedings, undertake the taxation of any bill of costs, and any proceedings relating to such taxation shall be subject mutatis mutandis to the rules applicable to the taxation of costs by any registrar of the Supreme Court of South Africa with respect to bills presented to such registrar for taxation. F ees (1) (2) 38. The Tribunal may, during the hearing of any matter by the Supreme Court, suspend the operation of any decision, ruling or order made by it until the Supreme Court has finally decided any such matter. Such a suspension shall not exceed a period of six months from the date of the Tribunal's decision, unless the Tribunal, on the application of the parties, extends such period. The fees to be paid under the Act shall be the fees specified in Schedule 2 to these regulations and shall be payable as follows: (a) By affixing revenue stamps to any document concerned, which stamps may be cancelled by a receiver of revenue or the Registrar; or (b) by impressing a stamp on any document concerned by means of a die approved by the Secretary for Inland Revenue; or (c) in such other manner as the Registrar may direct. The Registrar may refuse to accept any notice or documents lodged with or served on him if not stamped in accordance with Schedule 2, and notices or documents so refused shall not be admissible in any proceedings until duly stamped in accordance with the fees prescribed. Service of documents (1) Any notice or other document required by these regulations to be served on or sent to any person may be sent to him by pre-paid post at his address for service or, where no address for service has been given, at his office principal place of business or last known address, and every notice or other document required to be served on or sent to the known address, and every notice or other Tribunal may be sent by pre-paid post to the Registrar at the Patents Office, Pretoria.