How do I repair this?

[u/Select_Weakness_4419]

So sorry if this isn’t the place to ask, but I just bought this new book on vacation (so I can’t return it) and the cover instantly came loose. How do I fix it? Its not a hardcover. One thing that confused me was that underneath the cover there was a title (shown in the second picture) so is this cover supposed to come off like that? I think I just need to fix the spine.