I am sorry to hear this, too, but darn it - THIS IS WHY WE HAVE ARTICLES IN THIS SITE an a great newsletter. Please read our articles and sign up for our newsletter.
We already warned people what could happen if you sign those health waivers in the affirmative.
I am just glad you got any credit at all. The cruise line could have chosen not to give you anything because it is the passenger's responsibility to have insurance for unforseen illness.
In less harsh economic conditions I'll bet you would have lost that cruise, but as it is, they would rather have you onboard spending money. Best yet, they know it will almost feel like a "free cruise" to you so you spend even more.