Is there a way to recover audiobooks only backed up by iCloud ? Why was it not made clear that audiobooks cannot be restored from iCloud. I have a virtual library of audiobooks many of which have not been read and some purchase less than a week ago

my iPhone 5s had to be replaced. I purchased a new iPhone 6 As the 5s was only 6 months old. My audiobooks would not restore from iCloud. I quit using iTunes and pc when I got the 5s s I was under the impression the iCloud backup was good to go. My audiobook titles still appear but the actual content cannot be accessed. I have literally hundreds of $ in audiobook purchases, totaling more than the cost of the iPhone 6. What if anything can be done to recover or re download without buying all the books a second time?