Why do i wait for her?

I had been with this girl, we will call her "Olga", for about 2 1/2 years when she broke up with me for another guy. I was heart broken for months. and when i asked her why she did what she did all she could say was that it was my fault. she told me the story of when we were together (ill time warp it to that day)  and it was my Lil sisters birthday and my good friend was going to be there (my good friend is a girl) and well her name is Jill. Jill is a real close friend to the family her parents and my parents are real good friends and Ive known Jill since i was 4 (I'm 20 now). and Olga had to work that day and didn't want me to be at my sisters birthday because she didn't want me to  be around Jill after i don't know how many times i told her that me and Jill are good friends and we have been for years. Olga didn't like that and said she would break up with me if i went. i ignored her and said " then do it your not going to stop me from being at my Lil sisters birthday party. she broke up with me but soon got back together but used that as an excuse to be with that other guy saying i never loved her and left her for that other girl.which i didn't and would accuse me of cheating on her with Jill which never happened. (time warped back to the present) i was heart broken for months till she then called me and told me how she missed talking to me and was sorry for what she said and did. she then told me that the guy that she was talking to had left her for another girl and spent the weekend at the island and left her. soon after that she had came over and lets just say "made up" and has been talking for about six months now but doesn't want to be with me and always leaves me with heart ache. she tells me that shes never going to be with me ever again and that us together is a waste of time. she tells me to leave her alone and i try heard to do so but she then calls me and it starts right back were we left off. and i don't know what to do just leaver her alone and try to forget her again or wait for her to come around. if you have any advice i would love to hear it!