To switch your payment option, you first need to log into your Customer Zone
Once logged in, you can go to the customer menu and click on Account Information > Edit Account Details.
On the My Details page you can scroll down to Payment Method, select your preferred payment method and press Save Changes at the bottom of the page.
If you choose the Secure Credit Card option, please make sure you update your Credit Card details by following this guide: Manage Credit Card details
If you choose the Debit Order option, you can update your Debit Order details by following this guide: Manage Debit Order details