What is the ruling on a merchant and a buyer dealing with a usurious bank in Palestine, knowing that the bank takes a 7% commission from the merchant when selling to a customer in installments, and no Islamic bank is available?

This transaction is impermissible because the bank lends the price of the goods and recovers the loan amount with an increase (the commission) on it, and any increase on a loan amount is forbidden interest (riba). The Sharia-compliant alternative is Murabaha for the one who commands the purchase.