What is the ruling on purchasing a tablet device in installments through the bank, with an 18% interest rate on its price, knowing that the interest is determined by the company dealing with the bank?

Purchasing a commodity in installments through a bank for a price higher than its current cash price is permissible in principle, provided that the sale takes place after the commodity has entered into the bank's possession and responsibility, the contract specifies the number of installments and the amount of each installment, and that the price of the commodity does not increase due to delayed payment, nor are any penalties incurred as a result thereof.