Alipay is only available as a payment option at the time of registration. If you have already registered for an account using a credit/debit card or a PayPal account, you will not have the option to switch the payment method to Alipay later. However, if you wish to switch from Alipay to another payment method, you will be able to do so.
If you need any further assistance, please contact support and we'll be happy to help!