If the defendant in any such cause shall fail or refuse to accept and receipt for certified mail containing the notice of service and copy of the process and it shall be returned to the plaintiff or Director, the original envelope as returned shall be retained and the notice and copy of the summons shall be sent by open mail and the envelope and affidavit of mailing with sufficient postage of such open letter shall be filed with the clerk of court in which such action is pending and upon the filing thereof shall have the same force and legal effect as if such process has been personally served upon such defendant.
S.C. Code § 15-9-400