Wrongful termination (ADA)

Hi, all my sister was recently terminated from her job at Amazon. She has an accommodation which allows for her to take an extra two days off of work for chronic migraine. There was a clerical error, and those two days were not marked as part of her accommodation case. As a result, they terminated her position. She asked for it to be reviewed, and it came back as not approved. And then she appealed that and it came back Today, saying that they upheld their termination and gave no reasoning or further communication. This whole thing has been a nightmare that she really wants to work there and has been a really good worker. Does anybody have any advice on what to do or how to move forward with this incredibly ridiculous process? Is there any sort of phone number or contact or resource Anybody can help point me in a next direction?