S.C. Code Ann. § 23-47-55: 911 charges.

(A) For services for which a bill is rendered prior to the effective date of this act, for an exchange access facility that is capable of simultaneously carrying multiple voice and data transmissions, a subscriber is not liable to any person or entity for a different number of 911 charges than the subscriber has been billed for any such facility, and no service supplier is liable to any person or entity for billing, collecting, or remitting a different number of 911 charges for any such facility than is required by Section 23-47-50(A).

(B) For services for which a bill is rendered prior to the effective date of this act, no subscriber is liable to any person or entity for a different 911 charge on VoIP service or VoIP service lines than the subscriber has been billed, and no service supplier is liable to any person or entity for billing, collecting, or remitting a different 911 charge on VoIP service or VoIP service lines than is required by Section 23-47-67, or both.