Convert Csv file to Ebay File Exchange Format ADD,END and UPDATE ebay listing - repost

I need a way to Add, Revise, Relist & Remove my items on eBay using their FileExchange format based in CSV file (Provider) I am looking for someone who has experience with Ebay FileExchange format. I need the ebay csv is compared to csv provider and create a new one with price variations and stock. I also need to add all products by FileExchange Ebay via FileExchange. The CSV file of the provider has to create 2 files, one that adds the items and another that updates and stock price. Another issue is to up and down product listings. (End and Relist on FileExchange) and always compare the CSV of the provider (when stock are ok). The resulting csv files should not exceed 3000 items to avoid problems with the limit of Ebay.