How to cancel the mobile phone number of Tuniu Travel Network?

There is no logout option on web pages and mobile applications, and manual customer service can't help you logout. You can change your mobile phone number, provided that the original number is still in your hand, Tuniu will send a verification code to the original mobile phone to unbind it. If you can't get the information of the original mobile phone number, the customer service also said that you can't see the information in the background. I feel this is a program flaw, and you don't want to use it. Can only give up, can't take the initiative.