A group of people participated in an investment fund where each individual pays 10 dinars monthly. After six months, when there is capital in the fund, the person responsible for the fund, who is one of them, finances those who joined the fund or others to buy necessities (refrigerator, phone, washing machine, etc.) by purchasing the items for them in installments and applying a profit margin of 12% on the purchased item. Now the question is: Is it permissible for the fund manager to give the money directly to the buyer by authorizing him to purchase his need, and then he pays back the amount over several months with the profit margin calculated on it, or is it required that the manager buys the item for him and gives it to him?