At the conclusion of such hearing, the Department shall make and render findings concerning the subject matter and facts inquired into and enter its order based thereon. A copy of such order, certified under the seal of the Department, shall be served upon all parties thereto, or their attorneys, which order shall of its own force take effect and become operative twenty days after the service thereof, except as otherwise provided therein, and shall continue in force either for a period which may be designated therein or until changed or abrogated by the Department. Where an order cannot, in the judgment of the Department, be complied with within twenty days, the Department may prescribe such additional time as in its judgment is reasonably necessary to comply with the order, and may upon application and for good cause shown extend the time for compliance fixed in its order. A full and complete record shall be preserved according to rule of all proceedings had before the Department or any officer thereof, or any employee thereof designated by it for the purpose of conducting any hearing, on any formal hearing had and all testimony shall be recorded by the Department in a manner determined to be reliable and appropriate, and the parties shall be entitled to be heard in person or by attorney.