(2)The Rent Tribunal upon filing of petition under Sub-section (1) shall issue notice accompanied by copies of petition, affidavits and documents fixing a date not later than twenty one days from the date of service of notice requiring the landlord to submit reply accompanied by affidavits and documents, if any on which the landlord relies. The service of notice shall be effected through process server of the Tribunal or the Civil Court as well as by registered post, acknowledgment due. Notice duly served by any of these modes shall he treated as sufficient service.