You have several paths from which to choose. I think that you can go with a sad or despairing take on the loneliness that Margot feels. Perhaps a song by Suzanne Vega called "Luka." The experience of domestic violence and child abuse might be something that Margot could understand. Using this song might bring out Margot's predicament in a powerful manner. Another song that reflects the pain of alienation with some level of redemptive hope would be Sarah MacLachlan's song, "Angel." There is a definite sadness about being forlorn, but there is a sweet tenderness to it that Margot embodies. The ending of the story brings this out. I think that you could also pivot towards the anger that Margot's experience can suggest. This would involve pulling songs like Pink Floyd's "Comfortably Numb" or something even more angry such Eminem's "No Love." I think that you might also point to work by Nirvana and Kurt Cobain. "All Apologies" or "Rape Me" might serve as songs that tap into the subterranean anger that Margot experiences as she is forced to endure the silencing at the hands of the group. Any of these songs can be linked to what Margot experiences and might be able to bring out some of her own thoughts and feelings.