My big mistake..

The story is that I met a girl about 3 years ago in my city. I knew who she was but never talked to her myself. I Guess we just knew each other having the same network. Within a few months of texting and talking she fell very much in love with me and wanted to be see my all the time. But the problem was that at the same time I had met another girl I liked more at the moment. I ended up having a relationship with her the other, which lasted two years..

Now almost 3 years later it dawned on me how lovely a girl I threw away .. I tried to contact her again six months ago but she was in an on and off relationship. And the more I pushed her to give me another chance the more distance she took. Eventully the contact faded and we stopped texting ..

Now 6 months later I'm still thinking about her and how to get her back. Last time we talked she got mad and told me how I Hurt her and that it is hard to forget. What should I do to get her to give me another chance? Since she does not have social media, I can only contact her over snapchat.. But rumors says that she still with the dude. I messed Up but i want to do things right again. I care for the girl and would take any advice you guys have to offer. Im 26 and she is 24 btw.