How can I fix a stair riser that is the improper height?

My contractor put in new stairs to the basement, removing rug and increasing width of each step to 11 inches and creating a 22 inch wide landing at the top, to accommodate my physical limitations, I had measured risers, and thought all were 7 and 1/2 inches, which is a comfortable height for me (even though 6 inches is even better). However, when I tested out the stairs late Friday, I discovered that from the kitchen floor to the first step (the landing), there is a drop-off of 8 and 1/2 inches! It was distressing that having paid a large sum of money for new stairs, the step down to the first step causes my body to lurch forward. That one extra inch makes a dramatic difference. I knew something was wrong after the first try, and that's when I measured. The rest of the steps work just fine for me. I am way distressed about this. How can it be fixed? How did it happen? I have written out various ideas for a "patch", including eliminating the lovely landing and inserting another 4-inch high step at the very top as an intermediary, but none really make me happy. It is frustrating to know that if he had broken that one inch difference into small 1/8 inch units (or less) and distributed throughout the 12 steps, it would have been perfect. Any ideas what to do now "after the fact". thanks for any ideas.