Dead Space 2 / You Don't Own This Game

I tried to submit a ticket but that's been deliberately made very difficult.

The EA app does recognize that I have the relevant CD key activated for Dead Space 2, but in terms of downloading it and installing it it's just kicking out with 'we've canceled the download because you don't own this game'. Even though the library has it, the key is tied to it, etc. 

What's my next step?