What is the ruling on depositing money in an Islamic bank and purchasing a car from it through a Murabaha arrangement with a 12% increase, guaranteed by the deposit, such that the installments are paid from the deposit's profit? And what is the ruling on offering property documents instead of the car to facilitate the procedures? What is the correct Murabaha system? And what should I do about the installments I have already paid?

Murabaha to the one who promises to purchase is permissible under certain conditions and regulations. There is no difference between purchasing land or real estate. It is permissible for the price of goods in installments to be greater than their cash price, and for the deposit to serve as a guarantee for the sale, in the category of a pledge (rahn). As for paying installments from the interest of the deposit, if what is meant are profits from Mudarabah, then there is no problem. However, if what is meant are forbidden usurious interests from banks, then this is Riba (usury) which must be disposed of by spending it on general Muslim welfare.