“This device is linked to another Apple ID”
So, I got a notification from Apple Music saying I could get another 3 months free, but when I opened Apple Music and tried signing in, it said that this device is linked to another Apple ID. I bought this iPhone from eBay early last year, it was reset to factory settings before I got it. I’ve only ever added my current Apple ID to this phone, and I don’t even have another Apple ID! How can I fix this?