Alipay mobile phone binding has changed to a new number. Why is the SMS verification code still sent to the old number?

Please explain what kind of verification code it is. Generally, Alipay has two situations when trading. One is Alipay's verification code, for example, you need this verification code when you want to pay. The mobile phone number of this verification code was modified in Alipay, which has nothing to do with the bank. The other is the bank's verification code, which is sent by the bank when it pays fast or online banking. This mobile phone number was left by the bank and has nothing to do with Alipay. Two mobile phone numbers can be the same or the same.