Is mediation between a seller and a buyer of electronic balances for a specified commission permissible?

It is permissible to take a commission for brokerage in currency exchange if the transaction is permissible and adheres to Sharia (definition) guidelines, such as the actual taking possession (qabd) in the contract session or what substitutes it, like instant transfer. If you are buying for yourself, the mentioned conditions and guidelines must be met. After the balance is transferred to your account, it is permissible to sell it to someone else for a higher price if the currencies are different, provided actual possession (qabd) takes place. However, selling something you do not own to another person, without being an agent for the seller, is not permissible.