How can I help a friend going through alleged cyberstalking?

Hello,

I have a friend who believes she is being cyberstalked (e.g., that someone she knows has hacked into her computer and phone). While I believe her (in some aspects, although I think her concern has snowballed) and am trying to listen compassionately, I'm really worried for her emotional wellbeing. She won't talk on the phone (even to a counselor) because she believes that this person listens to her conversations, has access to her email, and can even infiltrate outside sources (e.g., crisis centers, the media, etc.). He hasn't made any physical threat to her (this is more just mental control, although she says he assaulted her years ago), but I feel that her worrying about his ability to watch her cyber activity is ruining her quality of life. How can I best help her?

Thank you!