Why is the order of uploaded files changed when sent to recipients?

I work at a law firm and most of the documents I need to send have to be in a specific order. I upload them in the order I need them. When the link is sent and I click on it to download the files (to see what the recipients are getting), the order is changed. Is there a setting I can change for this? I couldn't find anything. Please let me know as soon as possible. Other than that, this program is perfect for what I need.