Why is the margin in Forex considered a loan, even though the company does not demand it back after the loss of funds? So how is it called a loan if it is not returned?

What is known as leverage or margin, which a brokerage firm grants to a subscriber for trading, is a loan that brings a predetermined benefit to the lender. The company benefits from commissions on trades, and this constitutes Riba (usury). The resolution of the Islamic Fiqh Academy states that the broker’s condition that trading must be done through them leads to combining a loan with an exchange (brokerage), which is akin to combining a loan and a sale, prohibited by the Sharia (definition) according to the Prophet's saying: "It is not permissible to combine a loan and a sale..." And every loan that brings a benefit is forbidden Riba.