S.C. Code Ann. § 33-44-111 – Service of process

(a) An agent for service of process appointed by a limited liability company or a foreign limited liability company is an agent of the company for service of any process, notice, or demand required or permitted by law to be served upon the company.
(b) If a limited liability company or foreign limited liability company fails to appoint or maintain an agent for service of process in this State or the agent for service of process cannot with reasonable diligence be found at the agent's address, the Secretary of State is an agent of the company upon whom process, notice, or demand may be served.
(c) Service of any process, notice, or demand on the Secretary of State may be made by delivering to and leaving with the Secretary of State, or a clerk in the limited liability company department of the Secretary of State's office duplicate copies of the process, notice, or demand. If the process, notice, or demand is served on the Secretary of State, the Secretary of State shall forward one of the copies by registered or certified mail, return receipt requested, to the company at its designated office. Service is effected under this subsection at the earliest of:
1. (1) the date the company receives the process, notice, or demand;
2. (2) the date shown on the return receipt, if signed on behalf of the company; or
3. (3) five days after its deposit in the mail, if mailed postpaid and correctly addressed.
(d) The Secretary of State shall keep a record of all processes, notices, and demands served pursuant to this section and record the time of and the action taken regarding the service.
(e) This section does not affect the right to serve process, notice, or demand in any manner otherwise provided by law.