re-down deleted song

Hi frederik203,

Thanks for coming to Apple Support Communities for help today.

Double-check that you have followed the steps in this article: Redownload music

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

1. Open the iTunes Store app.

• On your iPhone or iPod touch: At the bottom of your screen, tap More , then tap Purchased. 
• On your iPad: Tap Purchased.

2.Tap Music. If you use Family Sharing, tap a family member’s name to see music that they purchased.

3.Find the music that you want to redownload, then tap it.

4.Tap the download button  next to a song or album."

This article may be helpful as well: If there's an issue when you redownload apps, movies, or other content from Apple.

"If you don't see the item that you want to redownload

• Make sure that the item is in your purchase history for your Apple ID. If you don't see the item in your purchase history, you might have purchased the item with a different Apple ID.
• If you don't see an app that you want to redownload, that app might not be compatible with your device. For example, an app that you bought for your Mac might not also work on your iPhone or Apple Watch.
• If you don't see items in your purchase history on other Apple IDs, the purchases might be hidden. Learn how to redownload hidden apps or unhide music, movies, TV shows, books and audiobooks.
• Do you want to redownload an app or other content that a family member purchased? If you have Family Sharing, you can download shared purchases."

If this doesn't explain the missing song, please contact Apple Support for a deeper dive.

Have a fantastic day!