If you are looking for a specific song pack that is marked as "down," you may need to check alternative stems communities or request a re-up from the site administrators. for a specific song's stems?
These tend to be less professionally recorded and are for the most part home recordings, which makes them more challenging to mix. Reddit · r/audioengineering White Paper on Remixes, First Sale, and Statutory Damages remixpacksclub down exclusive
The most probable reason. Major labels (Universal, Sony, Warner) employ automated bots that scan for copyrighted material. Sharing a studio acapella is considered a direct copyright infringement. If you are looking for a specific song