The Play MPE system allows you to send feedback to label/s about release/s you received from them. Please follow the steps below how to go about this.
1) Under Available Tracks/Releases section, click on the Cover Art associated with the release.
2) This will open the Release Information Page. From there, select the blue megaphone icon.
3) This will open the Feedback page. In here, you can enter your feedback about the release. You can also use this to request something from the label. You have to scroll down and click Submit once you are done.