what do you think I should do about this?

My friend i've known for 4 years through high school until now which is 5 years. She has friends which me and my friend call "the crew". She seems to always blow us off for the crew, when ever we make plans with her she will always agree to the plan and then she'll email us or call the day before or the day of and say BAD NEWS, she cant come. She'll say like oh im going out with my mom to do this thing or its someones birthday, My parents wont let me out or she just cant come. Even some times she will make the plans and then cancel them or just plan over them. We made a plan to go out once and she made me and my friend wait at the coffee shop at 10 at night waiting for her to get back from her "moms so called birthday" she went to a restaurant(remember that) even though we saw on facebook that she had plans with the crew to go to a concert, so next thing you know she calls us on the cellphone telling us shes not getting there til 11 ..then she finally comes.

Then when we have to get where we were suppose to go shes hungry for food...even though she already ate at her "moms birthday" little odd. So I think that was a lie. Okay so the point to this whole thing is that she always does this and we even had a talk to her about this problem, that she always plans over plans and just cancels them. What do you think we should do? because talking clearly doesn't work.