Cannot access Workspaces Application Manager links

Your issue appears to stem from lingering associations between your deleted AWS Workspaces and other resources (like your directory) which are preventing you from deleting those resources.

Here's a general process you can follow:

• Check for remaining Workspaces: Make sure that all Workspaces have indeed been deleted. Go to the AWS Workspaces console and verify this.
• Check for associations: Navigate to the AWS Directory Services console. Select your directory and click on the 'Actions' dropdown, then click on 'Deregister from WorkSpaces'. If you see a warning saying there are associated WorkSpaces, return to step 1 and make sure all Workspaces are indeed deleted.
• Check your applications in WAM (Workspace Application Manager): You mentioned that you're unable to access the WAM due to "Service Page Unavailable" error. Try to reach out to AWS support regarding this issue, as you should be able to access the page even if you do not have any active Workspaces. You will need to make sure all your applications in WAM are disassociated from your directory before you can delete the directory.
• Check for other service associations: If your directory is associated with other AWS services (like Amazon Chime or AWS SSO), you will need to first disassociate it from those services before you can delete it.
• Delete the directory: Once all Workspaces and associations with other services have been removed, you should be able to delete the directory from the AWS Directory Services console.

In case you're still facing issues, I would highly recommend reaching out to AWS Support, as they would have access to more specific information about your account and can provide more detailed assistance. AWS Support can be reached via the 'Support' menu in the AWS Management Console.