Assuming you purchased AI War through the Arcen Games store, you'll have to download it; that purchase got you a license key for unlocking the same downloadable version that acts as the game's demo. A non-English version of AI War was released as a physical retail game in some countries in Europe, but unless you specifically bought that from a store that is offering it (which we don't), you'll have to download the game, unfortunately. That physical version is also very old; there have been a lot of updates since then, including a brand-new game engine, so if you wanted the most up-to-date version of the game, you'd have to download the game all over again, anyway.
Sorry to hear about the difficulties in downloading the game. Retail games are very difficult for indie studios to do, though; they require publisher deals and don't earn as much money as digital distribution because of additional costs (manufacturing) and splitting the money between more parties, so indie games are typically digital-only. I'm not sure what suggestions to give aside from waiting until the end of the month to see if you have enough transfer left for the month to cover it. Maybe someone could host a zip of the game that lacks the music and expansions to reduce the download size? I think that might keep the size down to around 200 megabytes.