The catalog doesn't have a band, track, or album
All music is hosted on the service under license agreements with the copyright holders. If you couldn't find the tracks you were looking for, it means that they were not included in any contracts. Additionally, part of the catalog is only available to Yandex.Music subscribers as per the requirements of rights holders.
Yandex is invested in expanding the music catalog and tries to get as many rights holders involved as possible. Let us know what music you would like to hear on the service, and we will try to get the rights to host it. Unfortunately, we can't guarantee that we will acquire those rights.
If you want to post your own compositions on the service, read the terms for posting music.