Hope you don’t mind if I answer this question I got from someone. I know I have done so in the past and you have been gracious enough to tolerate it.
“Terry wrote, There has been strange activity going on in my house since I’ve lived here. Recently however I’ve been receiving strange phone calls that, because of many different things, I believe to be a ghost. The person answers many questions, all correct, about things no one should know unless they were watching me at that moment as well as throughout the day. I was wondering what I should do about this because the ghost told me that they are with other spirits and that those other spirits want to harm me and my sister. Also, is this even possible for a ghost to call my cell phone?”
Terry, ghosts can use the phone but I have never heard one tell me that other ghosts want to hurt people in the house. If I were you, I would look for the camera or person who is giving me calls. I think you have a live person who is aware of your fears and playing on them.