All perfect praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
There is nothing wrong with the extra amount that the seller charges on the credit card, which is the difference between the card`s price and the actual balance available on it. This is because this amount is in return for services and facilities. Moreover, the same ruling applies to the charging price. In addition, there is no harm in depositing money in that bank for charging the card.
At its fifteenth meeting (14-19-Muharam, 1425 AH), corresponding to (11-6-2004 AD), the International Islamic Fiqh Academy issued its Resolution No. (139) regarding credit cards carrying a balance, and it stated as follows: "It is permissible to issue credit cards carrying a balance and to deal in them provided that no interest is conditioned upon delay in repayment. It is also permissible to purchase gold, silver or currencies with this type of cards."
However, if the card is issued to a client who has no balance in that bank and he/she pays off more than the actual amount he had made purchases with via the card, then this isn`t permissible because this is a loan repaid with a usurious increase, which is unlawful. And Allah the Almighty knows best.