S.C. Code Ann. § 32-9-30

When a joint debtor has thus compounded a joint debtor who has not compounded may make any defense or counterclaim or have any other relief as against the creditor to which he would have been entitled if the composition had not been made. He may require the compounding debtor to contribute his ratable proportion of the joint debt or of the partnership debts, as the case may be, as if the latter had not been discharged. And the debtor who has not compounded with his creditor may set up by way of discount against such creditor the amount compounded by his joint debtor.