No seller, lessor, creditor, lender or bailee shall in the course of his business offer to any consumer or prospective consumer or enter into any written consumer contract or give or display any written consumer warranty, notice or sign after the effective date of this act which includes any provision that violates any clearly established legal right of a consumer or responsibility of a seller, lessor, creditor, lender or bailee as established by State or Federal law at the time the offer is made