Ahem, let me tell you a way. Download the 5sing client on your mobile phone, listen to this song that is prohibited from downloading, download a file manager, go to the settings and check Show hidden files, then enter the folder named 5sing, enter download, and then enter the file in the cache folder. You will see a song. Move it to another folder and the song will be downloaded. If you can't listen to the cached song. Just change the song tail to ".mp3".