To mange customers from your Eco Web Hosting account go to
Reseller Services: Your Greenhost Shop > Your Customers
From this page you can create new customers manually, view existing customers and delete customers if they have no product/services assigned to them:
By clicking on View Customer you will be able to view the contact details for this customer, including the security questions. Underneath the contact details you can also find details of assigned products, completed transactions and shopping baskets (purchases that were not completed):