Here is a breakdown on how Ring4 logins work.
You can only use your login credential once to create an account and Ring4 only allows one account per device. If your concern is to have multiple numbers, you can add multiple Ring4 numbers to a single account.
If you are confused about your account on Ring4 or think your phone number may have disappeared, this might be your support article.
On Ring4, you can only have one account under the same login credentials. However, you could have the same email associated with your Facebook or Google account.
Make sure to remember the method you used to sign in. If you sign in using Google, then you must sign in again using Google. A new Ring4 account is created each time if you log in using a different method.
I hope that helps! Still have questions? Create a new support ticket here.