Any party in interest aggrieved by any order or decision of the commissioner or by any rule or regulation adopted and promulgated by the commissioner may, within thirty (30) days after notice of it to other known parties in interest, make written request to the commissioner for a hearing. Within twenty (20) days after receipt of the written request, the commissioner shall hear the party or parties and shall give not less than ten (10) days’ written notice of the time and place of the hearing. Within fifteen (15) days after the hearing, the commissioner shall affirm, reverse, or modify his or her previous action, specifying his or her reasons for the action. Pending the hearing and decision on the hearing, the commissioner may suspend or postpone the effective date of his or her previous action. At any hearing before the commissioner, observance of formal rules of pleading or evidence shall not be required.