The law in plain English
Return deadline
Under S.C. Code Section 27-40-410, the deposit response usually has to be sent within 30 days of the move-out timeline described by the state rule.
Required notice
South Carolina generally does not impose a statewide deposit cap, and the landlord usually has 30 days to return the deposit and provide written notice of deductions before the enhanced willful-noncompliance penalty becomes part of the dispute.
This dispute type
Once the South Carolina deadline passes, the dispute stops being only about the deductions and becomes a deadline-compliance problem too. A landlord may still argue damage existed, but S.C. Code § 27-40-410 sets the clock for returning the balance and explaining any amount withheld.
Penalty leverage
If the withholding was wrongful or in bad faith, the exposure allowed under the statute is: Willful noncompliance: you can recover up to three times (3x) the amount wrongfully withheld, plus attorney's fees