Originally Posted by
WineCountryUA
the instruction states there is a explicit "upload" button.
Additionally the first refund request (where I browsed the file) was denied because no letter was "submitted."
I agree, but I think the "upload" button that they're referring to is the "choose" button or whatever your filesystem uses, when browsing for the file. I could be wrong. They also explicitly state that there's a "browse" button, but that one says "Choose File".
All I know is it worked for me and the letter must have made it along with the request, because it was processed.