I am so sorry that your mom and you have to worry about frustrating insurance snafus on top of everything.
Here is a thread on reddit that has some info about appeals processes that might help you:
https://www.reddit.com/r/personalfin...r_which_i_was/
My mom was treated for breast cancer in the 1980s, back when Blue Cross/Blue Shield took care of everything and insurance was a lot less complicated. Even then, we had one issue where they mistook a chemo drug as a wig because the name had the word 'plastic' in it.
They told us they didn't cover wigs and cosmetics. That was relatively easy to straighten out.