My form tutor is marking me absent on purpose, what should I do?

She is marking me absent on Thursdays and Fridays when I had been present everyday including these days. She has a problem with me because she dislikes my older brother so she dislikes me, I am not exaggerating. I get paid £30 a week to come in to reg (and lessons when available) but she has been cancelling it for a month without my knowledge by marking me absent. I sit at the front, I make sure I am seen and I come on time. She is not a reasonable person and I don't know what to do, she has marked me absent on the register so it makes me into a liar. What should I do? Thank you and have a great week :)