How do I get custody of my daughter if my ex has abused her?

I reported my daughter’s father for child abuse to the New York Office of Children and Family Services and they did an investigation. They said they could not prove he abused my daughter because she’s too young to say what happened, but they couldn’t rule it out, either. I know my daughter and I know he did something to her. Before this, we shared custody of her but now I don’t trust him and I want full custody, and for his visits to be supervised. I want to know whether I can appeal OCFS’s finding that the abuse wasn’t definitely proven and how to go about getting sole custody of her?