My first real love...

Dear redditors, I'm a male in the beginning of my 20's, I got togheter with my ex girlfriend when she was 18 and I was 21. We were both students everything went okay, we both had our flaws but it was doable. then I went on erasmus( we were togheter for 7 months), and everything went downhill from there. She was less and less interested, I made the mistake of overtexting her a lot of the times when I was drunk. She lost feelings for me. The moment she called me that it was over I asked her to stop contacting me.

Then I decided 2 months later to delete all her photo's and everything that reminded me of her. But 3 months after the break up I asked for a meetup because I think breaking up over the phone is stupid. She agreed and started texting me again but after 5 days she was putting really low effort in the texting again, I asked her to meet up.... She told me their was a 50% change she would love me in the future. I told her I don't thing 50% is enough for me and asked for no contact again, 2 weeks later I see her at a party she ignores me all night and I go to her and start a conversations.

In this conversation she says me all the things I did wrong and why I'm such a bad guy for her. It ended in a fight and since then I haven't seen her again. How could I have handle the situation better?, What do I do when I see her again (it's been 5 months), anny tips or notes in general?, Thanks in advance.