After receiving a written notice of non-receipt of payment under this subsection, a payor must, within 14 days thereafter, either (i) notify the obligee of the reason for the non-receipt of payment or (ii) make the required payment, together with interest at the rate of 9% calculated from the date on which the payment of income should have been made. A payor who fails to comply with this subsection is subject to the $100 per day penalty provided under subsection (a) of Section 35 of this Act.
750 ILCS 28/45