Rev-Enhancement

First phase - I am looking to build a website for customers to log in to in order to manage their program. The main areas I would like to focus on the design and functionality. I am open to suggestions on how this should be implemented, so I am looking for someone who is creative and has great ideas. I have a general timeframe of within a month for the completion of this project but flexible. The project should be of high quality and easy to use and navigate. Think of a private network each client/customer would have to access with a username and password to make changes to their purchase and change their products or ask for a refund etc... A retail site but not one that would sell products via the internet (confused?). The site would have to communicate with ZenDesk, and merchant account gateways provide reporting.