Upon the filing of a petition therefor by the attorney general with the public service commission, notice shall be given any such corporation requiring the corporation to appear before the commission at a day certain, not less than thirty (30) days, and to show cause why it should not be required within a reasonable time, not less than sixty days after such hearing, to obey the order of the commission made on such hearing. A copy of the petition shall be attached to such notice. Such notice shall be served by mailing it by registered United States mail to any executive officer of such corporation at his usual post office address.