Is it permissible for my friend to buy the charging cards sent to the bank's customer in exchange for the loan amount, whether after the customer has received them or before?

The first transaction between the bank, the customer, and the questioner's friend, which involves the bank purchasing recharge cards from the questioner's friend for immediate payment and selling them to the customer for deferred payment, with the customer receiving them directly from the questioner's friend, is impermissible. This is because the bank sold what it did not possess and profited from what it did not guarantee, thus rendering it akin to usury (riba).

As for the second transaction, which is the subject of the questioner's inquiry, between his friend and the customer, involving the friend buying the cards back from the customer at a lower price, this transaction is impermissible. This is because "a commodity that leaves one's possession and returns to it is annulled," making it akin to selling money for money of the same kind at a lower value. This becomes even clearer if it occurs before the customer takes possession of the commodity.

For the first transaction to be permissible, it must adhere to the rules of Murabaha to the orderer, and then the second transaction would be permissible if there is no collusion among the three parties.