Any producer on whose behalf an assessment has been paid is entitled to a refund of the amount paid by making written application therefor to the commission. The application shall be made within thirty days after the sale was made giving rise to the assessment and shall contain enough detail to enable the commission to find the record of payment. Refunds shall be made within thirty days of the date of the application unless the proceeds and the necessary information have not been received by the commission, in which case the refund shall be made within fifteen days after receipt of the proceeds and necessary information.