If your file is locked, it means that it's either still transcribing (if the status says Transcribing), or that you have reached our Fair Use Cap.
We try to make it as clear as possible on our pricing page that the Unlimited plans do come with a cap. Similar to how your cell phone provider may offer unlimited minutes or messages.
When designing these plans, we found that this cap would be enough for over 95% of our users.
If you have a large archival project, or if you have any questions about this, you can contact our Support team at email@example.com anytime.