Bought it on my Nook about ten years ago before I got a kindle and the book became obsolete in The uk. It’s set in a shopping g mall. I think written in the first person. End of the day no way out of the mall. All doors, exits disappeared. He meets more people along the way including a pair of girls who are fairly famous popstars. They have to learn to survive. I think possibly trapped for years - sickness happens. I think they lose a mate. There’s backstabbing etc. for some reason I think it’s Australian. And I think the title is just one word.