To turn off a frozen Clip Sport, try pressing down on the On/Off/Select button for 20 secs and then let go.
I use the same method if my Clip Sport will not turn on with the standard 3 sec button press.
And maybe make sure your device is working OK before you attempt a firmware update. The most recent updates attempted to fix problems for Audible users, but no new big features since Jan 2016.
