How to regain access to an account created using a disposable phone number?

Question

Computer networks

There are sites that provide the service of providing a one-time phone number for registering on sites, etc.
Let's say that a page on a social network or a mailbox was created using such a one-time number (now many email services require linking to a phone number).
Since the number is one-time, access to it is lost after registration.
And now, after a while, the site on which the registration was made requires confirmation of the phone number with which the registration was made (for example, if you enter the site from another PC). But the person no longer has access to this phone number (since the number is one-time).
- How is this problem solved?
- If before such a case arose, to bind a backup email address to the account, would it help?
Or will the site still require exactly the phone number with which the registration was made?
- How safe is it to register on sites using a disposable phone number?
After all, if the number is one-time, then other people can use it after you and they will be able to access your accounts (restoring access to your account using a phone number).

Answer 1

How is this problem solved?

In different ways, depending on what the owner of the resource came up with. There are resources that require it once. There are - which can resend SMS and in the absence of lock access. There are - which, when trying to let's change the password or rebind the mail - they will request SMS.
It may well, for example, when trying to untie a number and bind another. Or when you try to change the linked mail.
For a dustbin or something disposable - it will do for itself. For things that you plan to use - do not do this. Because then you want to say rebind the soap - and oops!