What is the ruling on an intermediary website deducting a 2% commission from the price of sold credit, acting as an intermediary between the seller and the buyer, while guaranteeing the buyer's right to a refund in case the sale is not completed?

Exchanging currencies among themselves is considered currency exchange (sarf), and for it to be permissible, it is stipulated that there must be real or constructive possession (qabd) without delay, based on the Prophet's (peace be upon him) saying: "If it is hand to hand, then there is no harm; but if it is deferred, then it is not permissible." Among the forms of constructive possession (qabd hukmi) that are recognized by Islamic law and custom are: the banking entry of a sum of money into a customer's account, such as direct deposit or bank transfer, or an immediate currency exchange contract between the customer and the bank, or the bank deducting an amount from one account to another at the customer's instruction. A delay in the banking entry for the periods commonly known in financial markets is excused, provided that the beneficiary does not dispose of the currency during this period until they are able to take actual possession. If the seller transfers the amount to the buyer's account at the moment of the contract, the transaction is permissible, and the intermediary's possession of the consideration on behalf of the seller is considered constructive possession.