You're community account here is different than your Visible account accessible at:
You utilize the email address you signed up with. If you've forgotten your password, try the Forgotten Password link on the member sign-in page.
If it's a matter of not being able to receive the code needed to sign-in via text, you'll need to chat with Visible to disable the 2 factor authentication. The chat button appears on the member sign-in page.
Note, however, if you successfully ported your number in to Visible from Verizon, your Verizon account was likely cancelled automatically and you'd need a new Verizon account while porting your number back. You'll need to request a port-out pin to do that but first need to be able to sign-in to your Visible account to request that.
Despite being Visible by Verizon they are separate business entities.