Purchased Song shows purchased but not available in Library. Song is also NOT hidden.

Hi,

I purchased the song Chandelier by Sia on the 29th of December 2014. It was one of my most listened to songs. I didn't notice that it went missing till I heard it on the radio again. Went to play it and it is no longer there. It still shows purchased in account settings. I also have the email showing the purchase. I have not hidden it, in fact I unhid all my music to see if it was bugged. But I still cannot find it. I can see it is not purchased when I go to the albums page and I can purchase it again. But obviously don't want to.

I would like to know how do I restore it in my collection. And what other songs have also gone missing in the time I have been using iTunes?

Edit: Shows Windows 6, but it is on Windows 10.

Regards,

Davin