Build a Website

We are a company which provide customer service for eBay sellers. We need to develop a simple tool which is able to manage different ebay IDs in the same interface. We need someone who familiar with eBay API and building ERP like tool. About our client: 1) eBay seller 2) Usually has more than 1 eBay ID Basic Requirement: 1) Able to access on a browser 2) Able to add more than 1 ebay ID 3) Support [login to view URL] / [login to view URL] / [login to view URL] / [login to view URL] ebay motor and else 4) 3 type of users, ADMIN, CLIENT, AGENT 4) An admin which allow to control the user access. (Like agent A can access a + b + c account or agent A can access client X's accounts which is a + b + c) 5) Eventhough a + b + c accounts is assigned to agent A. He can choose to view messages from 1 of the IDs by filtering. 6) Client can only view accounts which is belong to them 7) Admin can choose to login as an agent or a client to have the same view of the users. API Function: 1) Read and reply eBay message 2) Check eBay order history (item, buyer ID, tracking information, order date and shipping date) 3) Check eBay resolution center case (need all access, like send message, refund , partially refund, upload tracking number and else) 4) Access to active listing (need only access like searching active listing with an eBay URL, title and else) Tool Function / Feature: 1) Able to generate a work report for different client 2) An RMA module which allow agents to assign to return cases and there will be an interface for client to follow up the case. 3) Once agent made a decision for replacement / refund, we will send an email to client and there will be an interface for client to approve each case before taking further actions. **This is not one-time project. We need the same guy to add new functions for the tool on a monthly / bi-monthly basis.