Ebook not downloading

I purchased an ebook, prescribed university book. I struggled for 6 hours to open the book which never happened. I sent them a technical query on their platform, and called them to no response. 2 staffers responded to my query and requested more information which I did. Still no feedback they all disappear into thin air. I am writing exams and need the book to study, I explained this to them but they not interested in resolving their problem