Why can't I upgrade from CS5 Design Standard to CS6 Design Standard?

Hi. I recently purchased an upgrade for the Adobe Creative Suite 6 Design Standard from the CS5 version I previously owned. I've downloaded it and now when I try to install it, it's saying I don't have a qualifying product installed already to do it, and it's only giving me CS5.5 or CS6 as options for qualifying products. Can someone from adobe assist me on here? It is nearly impossible to get a hold of the phone support, especially in Canada. And I would need to figure this out in the next 2 weeks so that I could get my full refund if needed.

THANKS.