Unable to Download paid ebook on to DS application

Not able to Download paid ebook on this iPad - it is driving me mad.  The message that I get is "FULFILLING " nothing happens, no matter what I try I cannot manage this, it's very poor show for Adobe and I think I would avoid in the future, it's just not reliable and they nee to sort this ongoing problem out.  Wake up Adobe management help your customers and then smell the coffee once they're run away.