okay thank you for the additional information.
I would say then, that her behavior is rather extreme for the situation. When someone's reaction is bigger than the actual situation, than it's about something else typically.
I would not continue to apologize, (only once) for this, and then give her some space.
It is not productive on her part, to simply ignore your calls and not communicate about this (rather minor) incident. If it was a pattern of behavior that would be different. But you said that you are very attentive typically...
You can contact her once more and simply say that you are more than willing and open to talk with her about anything that is bothering her, including what happened with the phone. Let her know that without communication, you cannot know what she is thinking or feeling, and that this leaves you in the dark as to finding a solution.
Then do NOT contact her again...unless she reaches out to you of course. Give her some space and time, and she will very likely contact you shortly.
But, if she continues to do this disappearing act, when she is bothered by something, you will need to talk about how this is not appropriate nor constructive. Please click green ACCEPT button for this info. Thank you.