Here is the reply from GasBuddy.
Sorry for any inconvenience. Due to lack of use and resources, we are no longer able to support the Windows Phone app. Our product team is currently discussing whether the app should be be removed from Windows Phone altogether or a simplified version be made available in the future.
Thanks for your understanding.
In the meantime, GasBuddy can continue to be accessed from any mobile browser by going to:
http://m.gasbuddy.com
All the best in your search for low-priced fuel.
Regards,
Michael
GasBuddy.com
http://help.gasbuddy.com