We cannot resolve push notification issues from our end. Notifications are sent to your phone from Apple’s Push Notification Service (APNS), not WhatsApp directly, and it is entirely up to that service to make sure it is delivered properly.
Here are some troubleshooting steps for notification related issues:
This is an iOS issue that occurred after the release of iOS 9 and is outside of our ability to resolve.
This may occur when the sender unintentionally sends the same message twice. It may also occur when you have a poor connection. When this happens, the app cannot properly notify the server that the message has been delivered, so the server resends the notification.
The notification troubleshooting article may also help with other issues, such as if your Notification Center is not properly clearing or if your badge count is incorrect. Typically, the best and only way to resolve notification issues is to restore your phone to factory settings.
Important: Due to a bug in iOS 10, your notification sounds may not properly play until you restart your iPhone (press and hold the power and home buttons for 10 seconds).