How should I handle this facebook problem?

[Ryuuga Hideki]

Facebook is a social network, so while I do agree she was wrong not to respond to your comments I don't think you should've called her out on it. Your best chance, instead of severing your bond with words, is using said words to strengthen your bond. By severing your bond, you won't accomplish anything but insurance that she'll probably not speak with you over facebook. While strengthening it increases those chances by 30%. In your case apologizing is the beneficial thing to do. If she starts yelling or calling you out on it, keep calm and continue to apologize even so. That's the easiest way to solving this problem.