You can buy various content types (music, movies, or TV shows) from the iTunes Store. While downloading your purchase, the download may unexpectedly get interrupted because of different reasons (no/slow internet, hardware/software failure etc). Your download may stop before it is finished. Here is how you may resume your interrupted iTunes downloads:
IOS (iPhone or iPad):
1.Open the iTunes app
2.Tap Downloads (iPad: iTunes Store > Downloads; iPhone: iTunes Store > More > Downloads)
3.Tab the blue arrow to resume your download.
Computer (Windows or OSX):
1. Launch iTunes
2. Click Store > Check for Available Downloads.
A common issue/problem is missing Downloads tab. If you see no Downloads icon, tab Settings > > iTunes Store & App Store> your Apple ID > tap Sign Out and then sign in. If still no Downloads icon, it is possible that your download is completed. Launch the iTunes app then tap Purchased and check to see if your new purchases is listed there. If you are still having problems, simply restart your device.