7 U.S. Code § 4813 - Refunds
(a) Demand for refund; persons eligible
Notwithstanding any other provision of this chapter, prior to the approval of the continuation of an order pursuant to the referendum required under section 4811 (a) of this title, any person shall have the right to demand and receive from the Board a refund of an assessment collected under section 4809 of this title if such person—
(b) Form and time within which demand to be made
Such demand shall be made in accordance with regulations, on a form, and within a time period prescribed by the Board and approved by the Secretary, but not later than 30 days after the end of the month in which the assessment was paid.
(c) Payment of refund on submission of satisfactory proof
Such refund shall be made not later than 30 days after demand is received therefore  on submission of proof satisfactory to the Board that the producer, person, or importer—
 So in original. Probably should be “therefor”.