I had an issue a year or so ago, where I purchased a buyup to F from within my reservation a few weeks before the flight, quoted at $49 or something like that. When the CC charge hit, it was for almost $300.

Long story short, it was a big issue that the regular premier line didn't have access to deal with and I found out that you can get to the refund department by calling the regular premier line, and ask them to transfer (although I assume they need to pull up your reservation and you need to explain the circumstances for needing to be transferred). The two times I had to do it the reps confirmed they are open Mon-Fri 8 or 830 to 4 or 430 central time. (can't remember exactly)