Why would she be doing this?

There’s a girl I’ve known since high school. And we both had a baby a day apart. I had a boy, she had a girl. She seemed extremely jealous at first because she wanted a boy. Before this, we hung out my husband, I & her boyfriend and her. Her boyfriend never really gave much attention. He would be disrespectful and go in the room and shut the door. I thought we were friends me and her, I even helped her get in the apartment we use to live at. As time went on, we never hung out while pregnant. She was super cold for no reason. Then we both moved out of the place eventually. We had our babies; she would always ask to hangout and then not talk to me that day. I got tired of it and deleted her on fb. She re added me on my sons bday wishing him a happy bday and now hits me up saying hey girl and I’ll reply and she won’t reply for days. (She’s the one messaging me) and then she’ll make plans, we set the day, and she ignores me the whole week. I would’ve blocked her by now, but I’m so desperate into finding out her point of doing it. Also desperate bc her daughter and my son is a day apart and thought they could be friends. My son is now 13 months. I told her I feel like she has hate towards me, she says no. But actions speak louder than words… today she said hey girl, I replied, and again, no answer. What could be the purpose of this? Advice???