Download the game I bought

[Mudbill]

The Mac App Store version of the game is sold through Apple, thus you cannot use it where they don't supply it. Since it's been years I don't think you can ask for a refund anymore.

You're gonna have to use a different platform for your Windows PC, like Steam or GOG. Most likely you'll have to buy it again since there's no co-operation between all these resellers. Only possible alternative I can think of is that perhaps someone from Frictional Games can help you if you show proof of purchase, but I wouldn't hold my breath.

The game is often on sale on Steam for as much as 75% or 80% off, if you're considering it.