I tried purchasing a book on my Ipad. The "purchase" green icon was unresponsive, so I went onto IBooks on my Mac and successfully purchased and downloaded the book. I then went back to the IPad and tried to download the book. It apperas under my purchased books, but never downloads, I just have the black progess (or, in this case, lack thereof) bar across the bottom. I have rebooted the Ipad. No change. I cannot see how to download the book from the Ipad to rray and start again. What other options pls ?View...