Is it illegal for websites and app accounts to be unable to cancel or unbind mobile phone numbers? How should users protect their rights and interests?

There is only one way, change your mobile phone number and cancel. You can't let the original number have traces of purchase, and it is not easy for people behind you to know your information. If you are a salesman, explain the cause and effect of changing the mobile phone number to the customer after canceling it, so that the customer or your customer can not contact by phone first, but use information means to attach photos of your daily life so that the customer can. . . . . . I'm just an idea I will do it myself.