My daughter got beat up

So my daughter is 15 years old. She was beat friends with a girl called alexis when she was 13 they always had fun together then all the sudden alexis tells my daughter that seth (alexis' boyfriend) told her my daughter tried to get his number. I know my daughter wouldn't ever do that. Then alexis proceeds to say " i wanna fight someone right now im so mad" and my daughter tried to walk to her bike and go away but alexis' friends held her bike so that she was unable to get home (across a parking lot and field, my daughter couldn't run that far without being caught. So then she tried to walk away and alexis runs up behind her and hits her on the side of the head. Everyone was laughing so she was able to get her bike and ride home quickly but the alexis girl ran behind her and tried to catch her. Recently around last school year my daughter made a few friends and one was named kamryon. Everything was fine she was happy then all the sudden my daughter calls me telling me to hurry and come get her (shes about 2-3 streets over hanging with her "friends") she tells me that kamryon and about 12 other people are trying to beat her up. She says "kamryon wanted me to hang out so i went, then when i get there her and 12 or more people come out from behind this building. I had a bad feeling so i turned around and started walking away calmly. When i got across the field kamryon wraps her arm around my throats and pulls me to the ground and starts punching me over and over while in top of me. The other girls say do you want us to join in and kamryon says yea yea. An older lady sees what happening and breaks it up." By this time my husband and i arrive (the car was very slow to start) my daughter was ok but the teens filmed it and put it all over instagram and snap and just everywhere. My daughter has no friends at all everyone hates her. She cannot go outside because they chase her home she will not stand up for her self. And the police will not do anything the girls even threatened to kill me and my daughter for calling the police. Again the police did absolutely nothing. My daughter now panics when other people her age come near her even when im around she will not talk to anyone after we moved even if its not the same people she still panics and runs home. We have to home school her due to this. Some one help me