Section 308.168 - Effective date of and payment under an order to pay(a) Unless otherwise provided in the Notice of Assessment of Liability, payment of the assessment shall be due on or before the 21st day after service of the Assessment of Liability, under the terms of the schedule for payment set forth therein.(b) All payments collected shall be paid to the Corporation.(c) Failure to request a hearing as prescribed herein shall render the order to pay final and unappealable.