Replying is good! I think there was a similar thread on here awhile ago about a sub that would break off contact. The first thing that comes to my mind is- my Master would never put up with that. If you keep making excuses, or letting her make them, for her behavior- then she ends up being the one in control. I'm not just talking about punishing her here- but end the relationship. Maybe I am seeming harsh with this, afterall I don't know what your relationship with her is really like and maybe this is only a small problem- but I think that if you make it clear to her what you expect in terms of communication and obedience, and she repeatedly fails to deliver, then maybe she isn't the one for you.

In the other thread this was mentioned, and I will say it again, that if a person wants to be with you- they will put effort into communicating with you. Even times when I have had an emergency come up or had to be ripped away from communication with my Master, I'd text Him as soon as possible- usually only moments later- to let Him know what had happened. Your partner should put an equal amount of effort into communicating with you as you put into communicating with them. I think a sub, especially, has the duty to always be open and available to his/her Dom/me whenever they want them. (Of course this works both ways, and a Dom/me should also be there to support the sub when they need it.)

Anyway, I would recommend to give it one last shot- communicate to her how important it is to speak with you and the possible consequences of not doing it- and if she continues to ignore or disobey you, then I'd seriously consider ending it.