Barely any coffee rises to upper chamber after cooking

When I first bought it, it worked just fine even though I noticed that not all the coffee was brewed to the upper chamber.. There was always some coffee water still left in the bottom chamber when I would clean it. Then one day it started working great, where it would use all the water I put in it and make a full to the tippy-top cup of delicious coffee. I tend to grind the coffee not as fine as espresso but finer than a drip coffee maker. Now the bialetti only brings up two tablespoons of burnt coffee after it has been trying to brew on even temperature for 20 minutes. And I even put in a new gasket used the same ground coffee and it seemed to make it even worse (only 1 tablespoon of burnt coffee). Hope you can suggest something more to the juggular of the problem. Thank you. M Vekkos