Welcome to YT, Keith.
Pups like Missy who have been severely traumatized take time and patience. The most important thing is to give her time and space to come to the realization that life is not what she has been living; and that people are not cruel. As someone suggested, spend time sitting on the floor and letting her get used to you. Don't try to push her into socializing....just let her go at her own pace. It often takes years for them to come around and you learn that any little positive step is a huge milestone. I have two pups who came from a bad breeder. I adopted them in 2007 and they still have some issues with other people. They are sweet with me, but it took a very long time for them to trust me.