You can have a maximum of three active payment methods on your account at any one time.
If you already have three active payment methods on your account and you'd like to register a new payment method, contact our Customer Services team via the 24/7 Live Chat and they will be able to help you update your payment details.
If you don't have three active payment methods on your account yet you're still having issues registering a new one, get in touch through the 24/7 Live Chat option and we'll check the problem for you.