What are the legitimate alternatives available to Islamic banks to ensure a client's commitment to timely installment payments in real estate transactions, instead of imposing financial penalties?

If a bank sells a property in installments, it is not permissible to stipulate a penalty on the client for late payment, because it is usury (riba). To guarantee the bank's right, it can stipulate a guarantor (kafil gharim) or take a pledge (such as the property sold itself), while allowing the client to use it. It is permissible to stipulate the sale of the pledge without recourse to the judiciary in case of inability to pay. Among the other means are: stipulating the transfer of the account to the bank to deduct installments immediately upon the salary being deposited, and placing the defaulting client on a blacklist to prevent them from dealing with other banks.