Anyone know how Childrens Services works?

Recently I called about a mother who became upset with her child that she held him over the wrought iron railing in her 3rd floor apartment. She claimed if he didn't behave she would drop him next time. One neighbor called. I called. This was almost 2 weeks ago. There has been not one out to check on this family. When I was told of this incident it was to late to call the police. How else can I push the issue with them to know that her children may be in danger when she goes in to her rages. She has had some problems with them in the past due to an ex and his family calling all the time, making up stories for a custody issue. So I don't know if they will believe when someone else calls. I get so sick to my stomach when I go visit my friend who lives across the hall from her and I see her and the kids. I feel so bad for the children I want to take them away from that environment. But I'd don't want kidnapping charges on my hands. Any help please?