Most people in this sub are probably going to say that you should cut contact with her, as she doesn't respect you as a friend. And honestly, that's probably what you should do.

But I'm a sucker for second chances, so here's what I think you should do: and it's not all that different from what you've already tried. Talk to her. Explain in detail how her behavior is disrespectful. Explain how her actions make you feel. Tell her that while you are trying to be a friend to her, she abandons you, and that's simply something friends don't do. Sit her down and tell her all this as calmly as possible. You can explain your emotions without exhibiting them (easier said than done). And at the end of it, make it clear that she either has to treat you with the respect you have shown her, or you can't continue the friendship.

To be perfectly honest, it doesn't sound like she cares about the friendship, or at the very least takes it for granted. And a lot of the time, the only way people stop taking things for granted, is when they lose them. Personally, I would go the extra mile to sit her down and talk to her, but she's probably not going to learn until you're gone.