Albums are treated as an entity

Albums are treated as an entity. Imagine it like a physical album that is released as a CD. Once it is out, it cannot be changed anymore. Once an album is published on Jamendo a single track cannot be removed, nor can the order of the tracks be changed.

Make sure that your album is complete before you publish it.

But I must delete a track

You can delete the whole album from your account and then upload it again with the correct tracks in it. Note, however, that you will lose the statistics, comments, and likes of your deleted album. The new album will start at zero listens & downloads.