Only administrators of an organizational account can delete users. Please log in to the service account using your administrator account.
Go to the Users link or, if necessary, navigate to the Administration link, where you will find the Users tile. Clicking on the heading will take you to the user management page. Here, you can select the user(s) to be deleted by clicking the checkbox next to their name(s) and then clicking the Delete button at the top.
After clicking the button, you’ll see a confirmation prompt asking you to confirm the deletion. Once you confirm by clicking Yes, delete, the account will be permanently deleted. You can stop the process by clicking Cancel.