During the registration process, I got a message saying “Your email has already been registered”. What do I need to do?

The message means that your email address has already been used during a previous registration process, so there is already an account associated with it.
To access the account, you can follow the password recovery procedure:
• Follow this link https://www.thingsmobile.com/login
• Enter your username (the email address that you used to register)
• You will be sent an email with a link that you can use to create a new password