Amazon Cloud Player on Windows Phone Mango

In preparation for the Kindle Fire, I uploaded what MP3s I do have to the Kindle Cloud Player. Playing these on IE9 in Windows Phone Mango does work. The UI is a little slow and for some reason the volume on mine was crazy quiet. External amplification was needed. It’s a good example of the background audio features of Windows Phone Mango. So who do I have to talk to in order to get that volume issue solved?