As far as I have read here, the pwBPD will attempt to reach out to you for a supply when their new supply, your replacement, is not fulfilling them any longer... .it could mean that the relationship is over or that there is trouble within it OR that she has trouble in her life in another area. As I understand things; her reaching back to you is, under these circumstances, would be to replace your replacement.
Its odd that she would not say anything over the phone. I am guessing that she may not have the courage to do so or that her shame is causing her considerable pain to even speak up after you answer. pwBPD are hyper sensitive to emotions and the mere sound of your voice may cause a tidal wave of emotions that she simply cannot deal with and hence, she just hangs up. The one time I tried to call my ex after our b/u, she called the cops!
You know JRT, I found a letter from her from a few years back where she had probably done a push/pull thing (certainly not to this extent, maybe to a one day thing) and she said that she knew how wonderful I had been to her and that she just gets afraid. She goes on to say that she isn't proud of the way she treated me when pushing me away and that I certainly didn't deserve to be treated that way. She then apologizes, tells me how much she loves me, etc, etc... .
The thing is that I know by this point, and maybe back even by September when the calls began, that she knew she was in the wrong for doing what she had done. I know she knows by this point that whomever she is with, if it's a guy she isn't happy. She has never been happy with a man, unless he was gay. Then she didn't have to worry about the sex part. I want to contact her, but the real reason I don't is so that she has to live by her actions. She says that was what she wanted, and who am I to belabor the point anymore?
So I guess maybe she can't bring herself to really say anything because she feels guilty. She has a guilt complex anyway. I still miss her though. Not the last year her, but the one before that.