Does imposing an additional 3% charge for credit card payments, while not imposing it on cash or debit card payments, render the transaction unlawful, given the attempt to persuade the customer to pay with cash or a debit card?

First: There is no objection to taking the ticket price from the buyer using a credit card, whether the card is permissible or prohibited. This is because the sin of the forbidden in the prohibited card falls upon the bank and the client, and the seller has no connection to that.

Second: It is permissible for the bank to take a commission from the merchant in exchange for the service of facilitating the purchase and collecting the money. However, it is not permissible for the merchant to add this commission to the price of the commodity. The reason for the prohibition is that adding the commission causes the buyer who borrows from the bank (in the case of an uncovered card) to pay with an increase, which resembles usury. If the card is covered, then the bank is a guarantor and a surety, and it is not permissible to take a commission for guarantee and surety.

Therefore, it is necessary to refrain from demanding an increase from the buyer because it leads him into what is forbidden.