Just a follow-up to this thread: We applied for the refund on the website location, as noted in the thread. Some of the wording on that refund section makes it appear it is for ticket refunds, but it does also work for ancillary charges such as the double charge on the checked bag noted.

The refund request was acknowledged in approximately one day, approved in three, and appeared back in her bank account in about 5-7 days.

Much better than I anticipated.