I lose my sound notifications occasionally - probably due to updates. I turn everything off and on - both within the app and in my phone settings under apps - Etsy Seller - Notifications. If you have the message tone set too, then you could test it out by have someone message you. For sure if your get the sound for a message, the Cha-ching should work too.
* Also be sure your sound is up on your phone - there should be three settings - ringtone, media (games & videos) and notifications . I found that out once, when I had it turned down by mistake, and thought everything was fine because my ringtone was working!
