When you create your account you get 30 days of unlimited access. Once this time is up your Vault is locked and you are forced to upgrade to a paid account in order to access your passwords again. So unless you have backed up your passwords before this time you are out of luck. This isn't made explicitly clear when you first sign up.

Also the Firefox plugin "Keeper Fill" wouldn't remember my password so I had to type it in every time I opened Firefox.

When everything is up and running though it does what it's supposed to and makes auto-filling passwords pretty straightforward.