Build a back end data base based website with custom php with upload and download options through excel and picture upload

Before bidding read it carefully, I placed project three times before but no one so far is upto meeting my requirements, please bid if you have already a set up of professionals with you and you are a company and having at least more than 10 employees, please give me the relevant example of work you have done Details: My website will be having around 15 column data base which will be populate through excel upload option On front end different vendors and their products with pictures (around more than 25000 pictures) will be coming from data base, on main page Product group (expandable), categories (expandable) and subcategories (expendable) will be appearing like tree and branches. when a user select any product (standard product name matching functionality), its gives comparative prices of all vendors in a list (and suggested selection of the cheaper one automatically), users will be able to change the suggested selection of product, products categories, subcategories like an online store, shopping cart also required, with various payments methods, picture upload and excel based price upload option with standard names of products is required, product matching functionality on back end is also required, newsletter, email account, users registration, customised shopping card -checkout option, total saving indicator will be appearing, vendor accounts are also require, but their product will be loaded through admin panel only