How to resolve 'server error' when downloading iCloud data in Slovakia?

I had a full 200GB iCloud plan. Around 170GB of that was just photos and videos, so I requested a copy of my data from Apple in order to download it to my PC and free up space on iCloud.

Apple sent me the data in 4 separate files (46GB, 41GB, 40GB, and 36GB), but every time I try to download them, I get a "server error" just before the download finishes.

What can I do to fix this?

Also, why doesn’t Apple have support in Slovakia?

[Edited by Moderator]