35 ILCS 105/3-45
The tax imposed by this Act shall be collected from the purchaser by a retailer maintaining a place of business in this State or a retailer authorized by the Department under Section 6 of this Act, and shall be remitted to the Department as provided in Section 9 of this Act, except as provided in Section 3-10.5 of this Act.
The tax imposed by this Act that is not paid to a retailer under this Section shall be paid to the Department directly by any person using the property within this State as provided in Section 10 of this Act.
Retailers shall collect the tax from users by adding the tax to the selling price of tangible personal property, when sold for use, in the manner prescribed by the Department. The Department may adopt and promulgate reasonable rules and regulations for the adding of the tax by retailers to selling prices by prescribing bracket systems for the purpose of enabling the retailers to add and collect, as far as practicable, the amount of the tax.
If a seller collects use tax measured by receipts that are not subject to use tax, or if a seller, in collecting use tax measured by receipts that are subject to tax under this Act, collects more from the purchaser than the required amount of the use tax on the transaction, the purchaser shall have a legal right to claim a refund of that amount from the seller. If, however, that amount is not refunded to the purchaser for any reason, the seller is liable to pay that amount to the Department. This paragraph does not apply to an amount collected by the seller as use tax on receipts that are subject to tax under this Act as long as the collection is made in compliance with the tax collection brackets prescribed by the Department in its rules and regulations.
35 ILCS 105/3-45