It's not actually a direct charge - it's called an 'authorization charge' that is simply to determine if the card is legitimate - after a week or so that money is refunded back to you by your bank anyway so don't worry about it. If you card isn't being accepted by the system there could be any number of causes for it, which unfortunately don't often have an easy fix. A lot of players just abandoned using credit cards for subs and went with other payment methods, such as Paypal, or prepaid time cards.