Paid extension & requires registration --> removed (for now).
This is not specified on your Firefox Add-ons description page (French version).
Be clear, guys! If you want to make money with your work, and this is more than fair, why don't you offer a completely and unlimited free version with short (and smart!) vocal ads inserts?
More listen time --> more ads --> more $!
Then, if someone wants to remove the ads inserts, he can subscribe & pay.
Try it!

With friendship, and deep respect for your efforts,
Paolo