Cps isn't helping me!

Please help!!!

What can I do to help 3 children that I know??!! Cps has been called on their mom numerous times and they don’t do anything!!! I know she abuses (physically and verbally) these kids because the older one confides in me. Idk what to do if even cps isn’t doing anything!! Who else can I call?? I don’t even know their address!