Just in case anyone hasn't figured out how to download: I had to open Playstation Store so it would update, then go back to the message for the attachment to be active. After that, the attachment was selectable and it went right to the store where I was able to redeem and download.
At first I couldn't do anything with the attachment. Not sure if it was a timing issue or not, but this worked for me.
Hahahah, you've gone and died, have you? Well, what'll you do next? Going to just give up?