(a) The mortgagee or trustee granted a power of sale under a mortgage or deed of trust who seeks to exercise such power of sale shall file with the clerk of court a notice of hearing in accordance with the terms of this section. After the notice of hearing is filed, the notice of hearing shall be served upon each party entitled to notice under this section. The notice shall specify a time and place for the hearing before the clerk of court and shall be served not less than 10 days prior to the date of such hearing. The notice shall be served and proof of service shall be made in any manner provided by the Rules of Civil Procedure for service of summons, including service by registered mail or certified mail, return receipt requested. However, in those instances that publication would be authorized, service may be made by posting a notice in a conspicuous place and manner upon the property not less than 20 days prior to the date of the hearing, and if service upon a party cannot be effected after a reasonable and diligent effort in a manner authorized above, notice to such party may be given by posting the notice in a conspicuous place and manner upon the property not less than 20 days prior to the date of hearing. Service by posting may run concurrently with any other effort to effect service. The notice shall be posted by the sheriff. In the event that the service is obtained by posting, an affidavit shall be filed with the clerk of court showing the circumstances warranting the use of service by posting. If any party is not served or is not timely served prior to the date of the hearing, the clerk shall order the hearing continued to a date and time certain, not less than 10 days from the date scheduled for the original hearing. All notices already timely served remain effective. The mortgagee or trustee shall satisfy the notice requirement of this section with respect to those parties not served or not timely served with respect to the original hearing. Any party timely served, who has not received actual notice of the date to which the hearing has been continued, shall be sent the order of continuance by first-class mail at his last known address.