Can't delete schemas from cloud directory even when there is no cloud directory

It's understandable that you're concerned about being charged for Directory Services when you don't have any active cloud directories. The situation you're describing with sample and managed schemas is actually normal and not the cause of your charges.

Sample schemas and managed schemas in Cloud Directory are provided by AWS as templates and cannot be deleted directly by users. These are read-only templates that AWS maintains for your convenience when creating new directories.

The charges you're seeing for Directory Services are likely not related to these schemas. Instead, there might be other Directory Service resources that are active in your account, possibly in a different region than you've checked. Here are some steps you can take to identify and remove the source of the charges:

1. Check all AWS regions for any active Directory Service resources. Sometimes, resources can exist in regions you don't frequently use.

2. Use the EC2 Global View to see all your EC2 resources across regions, as some may be related to Directory Services.

3. Review your detailed bill in the Billing and Cost Management dashboard. This can help you identify the specific Directory Services charges and their associated resources.

4. Look for any lingering components like snapshots, backups, or other related resources that might still be incurring charges.

5. If you had an Amazon WorkDocs site that was removed after December 1, 2023, check if there are any associated Directory Service directories that are now being billed.

If after checking these areas you still can't locate the source of the charges, it's recommended to contact AWS Support. They can provide a detailed breakdown of your charges and help identify and remove any resources you're no longer using.

Regarding removing Directory Services from your account entirely, this isn't typically necessary or possible as it's an integrated AWS service. The goal is to ensure you're not being charged for resources you're not using.

Remember, the sample and managed schemas you see listed are not the cause of your charges and cannot be deleted. Focus on finding and removing any active Directory Service resources to stop the charges.
Sources
Why am I being billed for directory services? | AWS re:Post
Create an Amazon Cloud Directory - Amazon Cloud Directory
Create Your Directory - Amazon Cloud Directory