Hello Ebony 50,
I would be be concerned too if I was not able to update my iPad. If you have not resolved the issue, I recommend following the steps in the article below for an issue like this:
As always, it is a good idea to create a backup before hand:
Additionally, if you cannot play your purchased song, I recommend deleting the song and downloading it again. You can delete the song from your iPad by swiping from right to left over the song and then tapping delete. Next, you can download the song by following the steps in the section titled "iPhone, iPad, or iPod touch" in the following article:
If you are still not able to play the song after redownloading it, you can report an issue with these purchases using the steps in this article:
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