I’m sorry about the trouble some people have reported with digital and ebook formats. I’m hoping these things can resolved. I want my readers to be able to read my work in whatever format they like best and it’s frustrating when things beyond my control prevent that. Contacting the vendor is the best way to resolve problems with the book you purchased. I do my best to encourage my publishers to release versions without DRM, but customer voices make a real difference as well, so you could contact them as well.
How do I get my Kindle to update my ebook version for Words of Radiance, or other of your books?
See this page for which of your Kindle books have updates available: https://www.amazon.com/mn/dcw/myx.html#/home/content/booksAll/dateDsc/
And this page says how to turn on automatic updates (off by default): http://www.amazon.com/gp/help/customer/display.html?nodeId=201252670
iBooks and Google Play will both update your ebooks automatically whenever there is a new version available.