Any person aggrieved by any ruling or decision of the pool with respect to any assigned risk policy of workers’ compensation insurance may file a written appeal to the superintendent, within thirty days following the ruling or decision. Upon receipt of an appeal, the superintendent shall schedule and hold a full hearing, on at least ten days’ written notice to the parties affected, of the subject matter of the appeal, and after consideration of all matters presented at the hearing, as well as information available to him from the records of the insurance department, the superintendent may affirm, annul or modify the appealed ruling or decision, or take any other action with respect thereto determined by him to be fair, reasonable and nondiscriminatory, under all the circumstances. All testimony and other evidence on which the superintendent bases any decision under the Workers’ Compensation Assigned Risk Pool Law shall be in writing, directed to the parties affected and filed of record in the insurance department.