Why I'm billed for EKS service even though I do not see any cluster in my account?

Hi. Assuming you have deleted all clusters at correct region, EKS charges will not increases any more from here. So you can identify whether unnecessary resources are still existing or not.

If you suspect that unwanted resources remain, you can remove them by following these steps. https://docs.aws.amazon.com/eks/latest/userguide/delete-cluster.html

1. Go to Cost Explorer -> Choose Date Range in right pane
2. Granularity -> Daily
3. Dimension -> Cost Category
4. Servie -> EKS

Note: If you remove the "EKS" from Service filter leaving it blank and put "Service" in "Dimensions", you can see all the costs and where those coming from.

This would show you when you were charged for EKS and are you still getting charged for that or not.

Most likely you had this cluster earlier, which is not running anymore and charges are for past usage. Refer EKS guide for more information.

If you want to setup alert, you can consider setting up AWS budgets and configure alarm on those, which would notify you, if you cross the defined usage threshold.

If you have logs enabled, CloudWatch log group can generate some costs as well. Check if you deleted the log group.