The file extension must be .mp3 , .m4a , .flac , or .wav . Delete the file immediately if it ends in .exe , .bat , .zip , or .apk .
Toggle your app settings to "Download over Wi-Fi only" to save mobile data. Safety Warning Against Illegal Download Sites
If you use an iOS device, purchasing the song via the iTunes Store downloads a high-quality 256 kbps AAC file (M4A format).