A.R.S. § 44-1204: Payments of interest on obligation involving more than the maximum permitted by law on counterclaim in action brought on obligation; action to recover payments of interest in excess of principal on usurious obligation

In an action to recover on an obligation whereby there is contracted for, reserved or taken, a greater rate of interest than the maximum permitted by law, all payments made in money or property may be pleaded as a counterclaim or set-off. If such payments exceed the amount of the principal, judgment may be given in favor of the defendant for the excess, with interest at the rate of ten per cent per annum. If such payments exceed the amount of the principal of the debt or obligation, an action may be maintained to recover the excess.