This part shall apply to all contracts and shall apply to all retail agreements in effect which have no expiration date and are a continuing contract, and shall apply to all other contracts entered into, amended, extended, ratified or renewed after May 16, 1977. This part shall apply to and be binding upon all suppliers, all successors in interest or purchasers of assets or stock of suppliers, and all receivers, trustees or assignees of suppliers. Any contractual term restricting the procedural or substantive rights of a retailer under this part, including a choice of law or choice of forum clause, is void.