iBooks won't download previously purchased book
So I was having issues with a certain book that I've had downloaded on iBooks since it's release back in 2011 so I removed it from my laptop to immediately redownload it hoping that would fix the issue. Instead I get the 'buy' tab and when I click that it says 'A family member has already purchased this, and it is available for free through family sharing' problem is this is the only account in my family, my mother doesn't use iTunes or apple books. Also when I hit the Okay button it immediately hits me with an error page.
I just want my book back... or to be able to purchase it again.
MacBook Pro (Retina, 15-inch, Mid 2015), iOS 11.3.1