WEB Invoice System

I need WEB Invoice System with 2 logins 1) login for Admin 2)login for Customer Admin should be able to update Stock Information and receive e mail notification about purchase Customer should be able 1) Create new Invoice 2) See on time information in stock 3) add item from stock to invoice 4) Pay using pay pal service The system work: 1) when customer confirm purchase stock information should be updated 2) when admin updates stock information , customer should be notified 3) when user submit purchase , invoice should be saved, admin and customer should be notified via email 4) in email invoice should be attached in PDF Format Project should be in MVC5 or MVC6 with Entity Framework and sql server( could be Express) Invoice should have look like on the page. Information about stock should appear in Modal window. When Admin changed stock information the Stock Page should be refreshed automatically and Customer should be notified. I need also unit test for WEB Performance . I need emulate situation when 1000 customers made a purchase of the same item in the same time.