Advice please! 😊

So me and my mom have always had a bad relationship. She's always been emotionally abusive to me and now that I'm older and have confronted her she just continued with her mind games. Well I'm still in contact with her because she's my daughters only grandparent and I don't want to keep my daughter from her grandmother because that's what my mom did to me. Well she's constantly putting me down and I hardly talk to her because I can't stand her and today she sent me a rude message saying since I'm her kid I NEED to reply as soon as she messages me. I'm 20 but I've been well on my own for some time now and I don't feel like she has this authority over me. She's always been my main concern because she's manipulated me into thinking so. I've spent my whole life doing for her and trying to please her. She keeps messaging me and making me feel bad for not talking to her. I know I could easily just reply but she's so emotionally draining. I guess the advice I'm asking for is; am I obligated to wrap myself around her finger again? I have a life, I'm busy and she's not my main concern... am I wrong for feeling this way?