Spotify uploads the music exactly how it was sent to them. The tracks are mixed up because that is how the artist sent it.
The best thing you can do is try to contact the artist online and see if they can correct it. Usually the record label has to take down the release and re-release a new release with the correct informaiton to fix this.
I found the same problem on an album I like and after I contacted the artist they didn't send Spotify a new release for a whole year. It's a bummer, but only the artist can fix the problem.