Downloading issue on iTunes store

See the following Apple articles:

Redownload music in the iTunes Store app on your iPhone, iPad, or iPod touch

Redownload music - Apple Support

If there's an issue when you re-download apps, films or other content from Apple

If there's an issue when you re-download apps, films or other content from Apple – Apple Support (UK)

Use tones and ringtones with your iPhone, iPad, or iPod touch

Use tones and ringtones with your iPhone, iPad, or iPod touch - Apple Support

but it failed not a single percentage of downloading is showing

Check -> Service & Wi-Fi.

If they are On, turn Off Hotspot & VPN.