Refuse to return

I bought a book at the branch in mall of africa, only to realise its not what i wanted,. When u went back to exchange for the book i wanted, they refused saying its damaged. I literally read 2 pages of the book and it was in good condition. I left the book with them since i have no use for it. Just disappointed at the book shop that allows people to read books in shop telling me a book is damaged after reading 2 pages.