Is it permissible for a merchant to deal with a shopping center that forces him to reduce a percentage of the price of his goods in favor of a usurious lending company?

The transaction in which a usurious bank pays the price of an item for a buyer, and then charges him installments with a usurious increase, is a prohibited transaction. It is not permissible to assist in it by providing furniture or anything else, due to the Almighty's saying: "And do not cooperate in sin and aggression. And fear Allah; indeed, Allah is severe in penalty." As for reducing the price of the item with your consent, that is permissible.