A locked workspace means billing, not data loss.
Why it happens
A payment failed and collection did not succeed.
The plan lapsed or was cancelled and the paid period ended.
You downgraded and this workspace is above the number your new plan includes. On a downgrade, extra workspaces lock rather than being deleted, and the product picks which stay open by your plan's limit.
Nothing in it is deleted
Your chats, docs, Watchlists, Collections, brand and voice are all still there. Locking closes the door, it does not empty the room.
Getting it back
Settings, then Billing. Update the payment method, or start a plan that includes this workspace.
It opens again as soon as billing is current. There is no support ticket needed and nothing to restore.
If you are not sure which problem it is
The message tells you. A payment problem says the payment needs attention. A lapsed plan says the plan ended. A downgrade says the workspace limit was passed.
If it says none of those clearly, send us a screenshot and the workspace name.
Your other workspaces
Only the workspaces above your limit lock. The ones your plan covers keep working, and you can switch to them in the sidebar.