If you like to remove a workspace from your subscription, you can follow the steps from this help article.
Delete your workspace
Step 1. Visit your Workspace settings by clicking your name in the top right and selecting Settings.
Step 2. To delete a workspace scroll down to the "Danger zone" and press delete my workspace.
Step 3. Confirm and press Delete.
Deleting suspended workspaces
If your workspace is suspended because the trial expired you won't be able to visit your workspace settings anymore.
To delete it click on Your subscription, you can delete it at the bottom