What do I do with my iphone?

So I got my iphone a few months ago from AT&T and I'm on a family plan, I kept the box and receipt, the iPhone was great at first but now it has a trillion problems, the volume doesent work, it turns off in mid call, and it lags ect. Apple doesent do *** to help, now is there a way that I can remove myself from my family plan without having to pay an early termination fee? If not what do I do?

Does this affect your family/relationships in your personal life?

Or was this a mistake and in the wrong category?