I contacted them directly and they did respond pretty quickly. Unfortunately it didn't do much good.
However, I did manage to fix it myself. If you have created a backup, you can re-install the app and restore from the backup. If you don't have a backup, but do have the app on another device with your passwords (I had it on my tablet), then you can create a backup and email it to yourself. Then download it on your other device to restore your passwords.
Unfortunately if you don't have a backup and don't have it on another device. Then you've probably lost your passwords.
I have managed to re-create the issue simply by adding/removing a fingerprint on my phone. Once you do that, the app master password and fingerprint no longer works. So it is an issue they need to fix.
