How should I treat a girl who rejected me?

She had a crush on me for a long time. Her friends kept telling me she likes me. We became closer and things were looking good. We went out and kissed few times. But then she rejected me. First she started to be more distant when we met somwhere where was more people. Then it took her forever to reply to my texts. When i asked her how it is between us she just said I dont have time now which was obviously lie. Four months later she had someone new. We didn't talk like for three months. Now when we talk it is mostly making fun of each other and teasing. I mean we are friends and we see each other often cuz of lot of mutual friends. When we say hi and i dont smile she is like why dont you smile and stuff. I would say she still wants my attention cuz for example once i was sitting at the table and she was behind me and i didn't pay any attention to her she started kicking to my chair, blowing to my ears and stuff. I dont want to give her any attention anymore. i would say i am too nice to her. I dont want to be mean just because she rejected me but still. When we interact a lot and she smiles and stuff it doesn't help to get over her. What do you think

How should I treat a girl who rejected me?
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