What does it mean when a girl?

What does it mean when a girl says yes to a date, but is absent when trying to place a day and time?

absent as is not responding to questions or statements about day and time. There was one point when she told me she was free one day, and wanted to come out and asked me if I was free that day. It just so happened that I WAS free that day, and I told her so. She stopped talking to me before I could tell her the plan and that day has passed without any word from her. I feel like an idiot.

I don't really feel like beating it out of her with 10 broken record messages and a lecture, but at the same time I don't think that would solve anything. I WOULD much rather love to call her instead, but I assume she doesn't like to talk on the phone with me since the last 2 times I tried calling she let it go to answering machine and continued to just text me after instead.

The thing that kills me the most is that on 3 separate occasions she has told me that she really wants to meet up with me. Her actions obviously speak differently though, which is making me lose a lot of respect, and fondness I had for her.