As a reseller of Himalayan Host Pvt. Ltd., you can create Company Users under you and assign them different roles like Billing, Sales and Support. You can choose to give them the rights and permissions as per your requirement.
Thus, you can enable the Billing User to List Transactions, Add Funds, etc., but not be able to changes the Name Servers of the domain name and so on. In effect, User creation would help you to assign fixed roles to persons of your company and assigning them different responsibilities to reduce your own workload.