The only thing I would say about Abby having a phone, is this; why didn't her mother try calling her that day if she had a phone. We know Libby's dad was calling her when they didn't show up. So if Libby did have a phone, she must not have had it that day, or it would have been called to see where they were. So she may or may not have had a phone and if she did, maybe she didn't have it with her and her mom knew that.