I too have experienced the "no sound" bug since the latest Boom 2 update.
Setup: iMac 27" late 2013, with B&W MM-1 speakers.
With the B&W MM-1 speakers plugged in, turned on and selected as output, when I start playing music or a youtube …
I have sent an e-mail containing my App Store receipt for Boom 1 on December 10th and again on December 12th and haven't heard back. Just making sure it reaches you.
Thanks.
EDIT: Just received the 50% discount by e-mail, thank you!