LYNN – The family of a Lynn woman missing for four days believes she is in danger and is praying for her safe return.Crystal Brown, 20, suddenly left her Western Avenue home, where she lives with her mother, Monday afternoon with $2 in her pocket and hasn’t been seen since.Her family says Brown is unemployed and has a learning disability. They believe she met someone on a phone chat line and may have fled to Boston.”I didn’t get no sleep now since she’s been gone,” Crystal’s mother Frances Brown said.Crystal’s sister-in-law, Tausha Brown, 21, believes Crystal met someone on the Boston Raven chat line. She even found notes with young men’s phone numbers scattered around Crystal’s bedroom, she said.The Browns are worried about Crystal because she stopped taking her medication and has a diminished mental capacity because of her disability, they say.”If she’s in a bad situation, she might not be able to get herself out,” Tausha said. “She has no past with running away. It’s really making us nervous.”The family says Crystal likely had a plan when she left, but says she usually comes home the next day if she spends the night somewhere else.”We want her home and safe,” Frances said.When asked if they could deliver Crystal a message, Tausha replied, “At least call to make sure she is okay. We love her.”Anyone with information on Crystal’s whereabouts should call Lynn police at 781-595-2000.