70. In all proceedings under this Act before the Registrar-(a) the Registrar shall have all the powers of a Civil Court for the purposes of receiving evidence, administering oaths, enforcing the attendance of witnesses, compelling the discovery and production of documents and issuing commissions for the examination of witnesses;(b) evidence shall be given by affidavit, provided that the Registrar may, if he thinks fit, take oral evidence in lieu of, or in addition to, such evidence by affidavit;(c) the Registrar shall not exercise any power vested in him by this Act or the rules made thereunder adversely to any party duly appearing before him without (if required in writing within the prescribed time so to do) giving such party an opportunity of being heard;(d) the Registrar may, save as otherwise expressly provided in this Act, and subject to any rules made in this behalf under section 84, make such orders as to costs as he considers reasonable, and any such order shall be executable as a decree of a Civil Court.