I reported a number of tracks almost a year ago through this process and received automated e-mails thanking me for the reports. I've not once received a follow-up reply of even "hey, we're working on it."
I know that Spotify has to work through the owner of the music to fix these sort of things, but I have a feeling for anything but a popular track, it's just getting ignored.
The tracks I reported:
3 tracks on The Chemical Brothers - Brotherhood, which were at their full length when I first listened to them, reduced to 30 second previews. (Case #: 02922190)
2 tracks on Hive - Bedlam, which have errors that suggest they were ripped from a damaged CD. (I have less hope for this one since it's back-catalog stuff that probably got quickly uploaded and forgotten) (Case #: 02748126, 02748129)
Does Spotify even care about these reports? Has anybody else had music that has sat around without a fix or any confirmation?