Did you actually unlock your build for an hour with the keystore password? If you don't and you build, you'll get a debug version.
That is more a stackoverflow / phonegap question: https://stackoverflow.com/questions/20196968/unable-to-upload-phonegap-build-apk-to-play-google-you-uploaded-a-debuggable-a
I would double check your signing keys.
If you haven’t tried this already please at the line <preference name="android-manifest/@android:debuggable" value="false" /> in your congif.xml file, this should work.