If my mother slipped and fell on wet super market aisle, why did the store refused to give her an incident report?

My mother was doing grocery shopping at a local supermarket when she suddenly slipped on wet floor and fell on her back. She wasn't able to get up for at least 30 minutes until my father arrived and helped her up but she wasn't able to walk so they sat her down. At first my father argued with them for not having a wet floor sign displayed. He was told they weren't mopping the floor, that was melted water from the freezer. Then my father requested to speak to a manager and my parents were told there is no manager on duty he is on vacation. This is something hard to believe considering it's a big chain supermarket and I don't believe they would let cashiers and stockers run the store while the managers on vacation. Anyway my mother was worried about her condition and didn't know whether she was able to work for the next couple days and asked for an incident report and she was refused every time she asked. They offered her Tylenol, which my mother didn't take. She tried to get up again but she couldn't so my father told them to call an ambulance. Luckily she didn't suffer fractures or any broken bones but two days later shes still hurting and isn't able to work. I'm very disappointed and angry with the way they treated my parents. Yes they are immigrants and English isn't their first language (they do speak English, they are US citizens) but that doesn't mean she doesn't have rights and it doesn't mean you can just send my mother home with Tylenol and complimentary bottle of water after she took a big fall and was injured. Why didn't they give her an incident report? Why didn't the manager or whoever was in charge come down to help her out but let the stockers and cashiers handle the situation? Why didn't they call an ambulance right away knowing my mom wasn't able to get up or walk? I would appreciate any answers or advice. Thank you in advance!