30 ILCS 540/3-2.5

If a vendor provides goods or services to an individual and requires that individual to pay all or part of the cost of the goods or services in advance of the vendor being paid for those goods or services by the State, then the amount of the individual's advance payment, and any interest under this Act attributable to the advance payment, that is paid by the State to the vendor is the property of the individual and, to the extent received by the vendor, must be promptly disbursed by the vendor to that individual.