Thanks for using Apple Support Communities.
For more information on this, take a look at:
iTunes: How to resume interrupted iTunes Store downloads
- From the Home screen, tap the iTunes app.
- For iPhone or iPod touch, tap More > Downloads. For iPad, tap Downloads.
- Enter your account name and password if prompted.
- Tap the blue download arrow to resume.
If you can't complete the download on your iOS device, you can download it in iTunes on your Mac or PC and then sync it to your iOS device. You can also transfer purchases from your iPhone, iPad, or iPod to a computer.
Best of luck,