My grandmother died of brain cancer about 20 years ago. About two weeks after she died I was hanging out over at my parent's place and my mom got a call–no number, no unknown number, just blank caller ID. She answered it, got quiet, hung up and went to her room without saying anything. When I finally got her to talk about it she said it was her mother, saying she was trapped and please come get her because they wouldn't let her leave, over and over again, and then the phone disconnected. I asked her about it a few years ago and she denied that it happened for a bit and then admitted that it had happened two more times that year and then stopped, but she didn't want to discuss it any more. – Santamente