815 ILCS 505/2B.1

It shall be unlawful in the sale of consumer goods or services for any person conducting a mail order or catalog business in this State, and utilizing a post office box address or a street address representing a site used primarily for the receipt or delivery of mail or as a telephone answering service, to fail to disclose the legal name under which business is conducted and the complete street address from which business is actually conducted in all advertising and promotional materials, including order blanks and forms.