App Does NOT Work

I purchased an ebook for my course, and initially this app would not open my account on my iPad/iPhone entering the correct username/password. Once the app would finally open into my account (the next day), it would crash as soon as the purchased ebook download completed. When I re-open the program, it gives an error message “Alert: Unable to open the book. Please delete and download it again." I have tried to re-download this ebook numerous times for the past couple of days and it will not work. My email to the AHA customer service has gone unanswered, and the website says there are no refunds on ebooks. I can’t access the ebook on my iPad/iPhone, so I wasted my money on this ebook! PLEASE FIX THIS APP ASAP!!!!

LLMedStudent about AHA eBook Reader, v5.0.1