O.C.G.A. § 13-5-9: Total or partial failure of consideration generally.

If the consideration for a promise, apparently good or valuable, fails either wholly or in part before the promise is executed, the failure of consideration may be pleaded in defense to the promise as provided for in subsection (c) of Code Section 9-11-8. If the failure of consideration is partial, an apportionment shall be made according to the facts of each case.