What can I do if my appeal is denied?

I have a medical condition that causes severe pain throughout my body when going through a flare up(which tends to last several months). My supervisor and HR told me to file for short term disability since it was impacting my ability to work. My companies disabilty coverage is through New York Life. The case manager I was provided has not been helpful. Due to a death in his family he wasn't in his office most of the time so I was talking to different people throughout my process. First they said my doctor didn't provide enough information so they sent more paperwork to be filled out, then they said the new paperwork they filled out had more information then the previous paperwork so it didn't look right and they denied my claim. When I talked to my case manager about what to do and how to get help he raised his voice at me and became irritated when I said I haven't gotten consistent help with my process. He told me the only thing left to do was file an appeal and hope the next group votes differently. I've been out of work since 6/06/25 with no source of income and racking up debt in doctor bills and physical therapy on top of my monthly expenses. If my appeal doesn't go through is there anything else I can do?