If the problem is a bug in the Android firmware version update, then Amazon may not be able to help you.
I just hope Amazon doesn't upgrade our Kindle HDX 2013 to that version of Android. We may encounter the same problem.
I did notice from browsing the Android forum for Nexus 7 2013 that there are lots of problems with the latest Android firmware. One I noticed was the "Sleep of Death" where the Android just shuts down spontaneously.
Here is the link to that thread:
http://forums.androidcentral.com/goo...ing-sleep.html
I've never noticed that problem on the HDX 2013.
Here is a quote from that thrad:
"For some reason my new N7 2013 (my first Android device) is crashing/turning off, but only while its asleep. Its not consistent, but it is annoying. Ive tried resetting to stock but I still have the issue."