We weren't together that long. Only 4 months, but we hung out every day, or spoke on the phone for hours, so it felt more like 4 years

She lied a lot, or at least I think so.. When we broke up (we did it on the phone) she even changed her number afterwards, I couldn't reach her for 2 months (worst pain in my life, and I thought everything was my fault). When we finally met (in a work thing) she just started flirting with me, acting like nothing had happened.

I was still acting desperate and I took all the guilt, made huge apologizes for things I never did, just trying to get her back...

I know she doesn't deserve any attention from me at all... The worst thing is that I have so much to say to her,,, how I've changed, and also finally being able to show that I'm angry for what she did... But I know she'll never care.

Despite all this she said two days before we broke up that I was her best friend ever, and the last time I spoke to her she claimed she still loved me.
I just don't get it and I probably never will.

She seems really unstable man. Don't believe her words, they are spoken without meaning and have a selfish motive behind them. As soon as you break up, under no circumstances should you even contemplate going back. Because it is doomed to fail guaranteed. You will hold grudges for what she has done and so will she. You will pick fights and low and behold you will break up, again and again. There is a post by truestory about it. I think you should give it a read.

http://www.theattractionforums.com/f...en-hearts.html

As for all the things you want to say to her, and show her how much you have changed, show her but not directly. Get on with your life, better yourself. That will be the best form of passive 'revenge'. Nearly all of us here have been in this situation, you are not alone. And you will learn from it.