Whats wrong with my band?

I've been with them since 09 and since there is this new bassist and singer, all they have done is ridicule me and joke around that they are going to replace me, it was "retainable" after the first week, but they've been doing it for 9 weeks. When i tell them stop, they say, THEN GO TO BAND PRACTICE. I try to tell them sometimes i can't get to band-practice because i have homework or something extra thats academic that has to be accomplished.