Usury forfeits entire interest; right of setoff; how forfeiture discharged; when time bars action or defense

(a) Any person, company, or corporation violating the provisions of Code Section 7-4-2 shall forfeit the entire interest so charged or taken or contracted to be reserved, charged, or taken. No further penalty or forfeiture shall be occasioned, suffered, or allowed. (b) The amount forfeited as provided in subsection (a) of this Code section may be pleaded as a setoff in any action for the recovery of the principal sum loaned or advanced by the defendant in said action. (c) No contrivance or arrangement between the parties to any such unlawful transaction or their privies, except an actual and full payment of the amount forfeited as provided in subsection (a) of this Code section, shall have the effect of discharging such forfeiture. (d) No plea or action for the recovery of such forfeiture shall be barred by lapse of time shorter than one year.