Depending upon the app, the process for contacting the developer may vary.
From the Start screen, swipe left to display the apps list. Alternatively, tap the Right arrow (located in the lower-right).
Tap the app.
Swipe left or right to locate then tap support or about. If 'support' or 'about' are unavailable, navigate: More > about [app name] > Contact [developer name] then skip to step 5. If the above option is also unavailable, feedback can be provided using Marketplace Ratings and Reviews.
Tap feedback and support or feedback.
If applicable, tap an email account in which to compose a message.