If you have already purchased SMS credit and all you want to do is change your credit card details, you can do so without purchasing new credit.
Click on the big green Buy Now button on the top right of your account.
Scroll down until you reach Billing Details.
After your first purchase, you will have the ability to use the card you've already entered.
NOTE: We do not store your credit card details! We process all our payments with eWay, so all we have is the last 4 digits of your card.
Use a New Card (update your credit card details)
Now, if you want to update your details, select Use a New Card and enter the new credit card details.
When you are done, simply click Update Payment Details and your credit card details will be updated.
If you want to update your details AND purchase credit, click on the green Confirm Payment button instead.