35 ILCS 638/70

Tax may be imposed on items not subject to taxation if those items not separately stated. If a taxing jurisdiction does not otherwise subject charges for mobile telecommunications services to taxation and if these charges are aggregated with and not separately stated from charges that are subject to taxation, then the charges for nontaxable mobile telecommunications services may be subject to taxation unless the home service provider can reasonably identify charges not subject to such tax, charge, or fee from its books and records that are kept in the regular course of business.