Why did my track disappear?All of our accounts come with a set number of upload minutes (check out our Pro page to see these limits). When you upload more than your allocated quota allows, your oldest sounds that don't fit will be hidden. If you visit your tracks page (https://soundcloud.com/you/tracks) you will be able to access any hidden tracks.
If you aren't over your limit, please check if the sound is listed at the following link. If it is, you'll be able to submit feedback by clicking its title there.