Actually, I can venture an educated guess at to why your Aromasin isn't working. I'm guessing you're not taking it with a meal that contains fat. Exemestane/Aromasin is a fat soluble AI, and in order to work properly it needs to be taken with a meal that contains at least 40 grams of fat. Without the fat, the Aromasin doesn't have anything to bind to, and will not be metabolized by the body. It is instead passed through as waste.
So in short, always take Exemestane with at least 40 grams of fat or it doesn't work.