When being a good communicator becomes a liability

I have two sisters, one older, one younger. (I was the oldest till I was 12 but that's another 6 posts.)

Of the three of us, I am the only one speaking to my mother. She would talk to my younger sister (who most certainly would not talk to her) but not my older sister (who might take a call).

My younger sister won't talk to my older sister, though my older sister would probably talk to my younger sister if the opportunity arouse. And either one of them rarely is the one to call me.

It really increases my phone call obligations.