Why do you have to wait so long for an appeal hearing?

I was denied twice and am now waiting for an appeal hearing. My physical and other conditions have gotten worse since my initial case was filed. I contacted the law firm that is supposed to be representing me, but they tell me that there is nothing they can do to help me get a hearing. I have called several times and provided them with more and more evidence that my disabilities have gotten worse, but they say that doesn't matter. I need help, my family needs me to be able to help, with the bills and provide us a better suitable.home to live in. We can no longer use the heat source that we have because my asthma has gotten so bad that I am not able to handle the wood smoke from the wood heat. What can I do to get a hearing?