Why can't I delete this song on my iPhone 5s?

The song "Happy" by Pharrell Williams randomly downloaded onto my phone one day. I checked that the "Show All Music" option in settings was unchecked - which if you don't know what it does if unchecked; only music downloaded from this device will be shown in the library. A relative, who uses the same Apple ID as me must have downloaded it, yet I don't know it would end up on my device if I had the "Show All Music" option unchecked in the first place? Plus, I can't delete it. I swipe on every other track, which presents me with the option to delete them, but this song does not seem to respond to swiping. Any help would be appreciated, I need to get this pathetic track off of my phone.

Go on your computer and go to your songs then you can delete them from there

That Apple ID downloaded it. But I bet their iCloud backup storage is what's keeping it there on all devices. It's in their iCloud so it replicates on all devices that the account is logged into. Can you log out of the iCloud account on the phone and then log in as your own? Best luck.