For most feedback you can use our Cloudshelf Feedback Forum
Cloudshelf Feedback Forum
If you come across something that is clearly an error, and in particular, any hangs or crashes, then filing a bug report is very useful. Simply tap the Submit a Ticket link at the top of the screen.
Please provide details to help us reproduce and fix the bug. Including your device type, OS version, steps to recreate and screen shots really help us in tracking down the problem.