There's a big difference between owning content, and having access to download content. The problem here is that you were not buying a version you could download and store on your system, and just play it back with whatever. So you 'bought' it while it was still under their control etc.

But like so many other comments here state: it's very much a known fact that 'buying' something like this is just renting it for a short time period. We must keep fighting for them to actually state this in bold text before you pay them.