A tag from a feed is wrong - is <amount/> instead of <amount>xx</amount>

Hello, 1. The problem explained: i have a script feed from a 3d party named „[login to view URL]” This script feed is getting all the products from the shop and generates an .xml file. The .xml file has an tag name generated wrong. Instead of <amount>quantity</amount> he is generating just <amount/>. (see print screen attched or generate the .xml feed with the help of the following link to see the wrong <amount/> tag) The link to generate this .xml is [login to view URL] (there are 4615 products so you have to wait 5 min.) 2. OBS: The amounts (quantity) of the products are set in the admin area. I need to know what was the error and how you correct it. I need to be able to generate the feed correctly with the 3d party script, from „[login to view URL]” ([login to view URL]) You will get acces to SFTP and phpmyadmin