I think I need help...?

I need to talk to my dad since we haven't for about 9 months. He calls and I ignore them. I can always tell when my step mom is arounf because he seems really really sad in his messages, and when she's not around he talks down to me(via voicemail) and picks at all my faults. I need to talk to him but if I do, he wins and I am too stubborn to let that happen. I just want him to go away and never be areound me again. He wants to talk to me, but only so that his life will seem perfect to his new little tart of a wife. This si too much stress for me, I am getting headaches, won't eat, ect. I just dont know what to do....