1) did you set up production environment (not sandbox) in your ApplePushChannelSettings?
//Create our push services broker
var push = new PushBroker();
//Registering the Apple Service and sending an iOS Notification
var appleCert = File.ReadAllBytes("YourCert.p12"));
//isProduction - development or ad-hoc/release certificate
push.RegisterAppleService(new ApplePushChannelSettings(isProduction, appleCert, "pwd"));
2) try to use
WithCustomItem("incidentId", "1");
3) maybe the reason is the wrong sound file name. I see that it doesn't have an extension.