If the email address that you put in the signup form is the one that you signed up to BB with, but has nothing to do with your Google Play email, then please signup again with the correct email, it should be working afterwards, maybe you will have to wait a bit for Justin to put you on the list.
I signed up with the correct google play e-mail address. I found an other way to download the app, I opened the link Justin sent me and I putted BB app in my wishlist. Then I opened my google play, found BB app in my wishlist and the download button appeared. I dont know what the problem was but finally I downloaded the app. At first looks fine, well done