All decisions of the commission shall become operative and effective upon service of the decision, in accordance with the provisions of subsection (a) of Kan. Stat. Ann. §§ 77-530 and amendments thereto, unless otherwise ordered by the commission or a stay is granted. The commission may grant a stay or suspend, in whole or in part, the operation of any order or decision of the commission in accordance with provisions of Kan. Stat. Ann. §§ 77-528 and amendments thereto. After the lapse of the time within which proceedings could be taken to obtain a review of such decision, no proceedings to obtain such review having then been taken, such decision shall be held to be conclusive as to the matters involved therein in any collateral suit or proceedings.