Reject calls with WhatsApp message Is there any app or any way to reject a call with a message sent via WhatsApp? Normally when we get a call there is an option to reject it with a pre-written SMS, but I was wondering if you can use WhatsApp to send these template messages.
Looking at WhatsApp FAQ, it looks like this feature is currently NOT Supported by WhatsApp.

In Summary, When someone calls you, you will see an incoming WhatsApp call screen. And you can tap on the message icon on the call screen to decline the call with a quick message.

But for Above steps to work, the Incoming call HAS TO BE WhatsApp Call and NOT the regular cellular call.

Hence, currently user needs to use native/in-built app Like SMS/Hangout to Reject call with message.