I call, and she's either (a) not home or (b) busy (as in she's doing something and can't talk, or the line is busy).
She called today at some point where I was asleep, so I call her when I wake up. The phone (our house is infamous for non-working phones) is breaking up something horrible, so she says she'll call me back. This was an hour ago. I call, and the line is busy.
This amuses me. This is also why I never call.
I will assume my father is on call and try again later.