Wonder Why

I just can't help but to wonder why my sister Lisa refuses to call me. I don't understand. When we do talk, she is wonderful, tells me she misses me and loves me, etc. but she seldom calls me (unless she wants something) and generally does not answer her phone when I call. She only lives about 15 miles away from me and I haven't seen her since Christmas.

I have some stuff from my dad that he wants me to give to her, and she refuses to make any specific plans to meet, and now appears to be avoiding my phone calls.

I just don't get it.