How do I silence incoming voice calls on WhatsApp? I've been forced by my relatives to install WhatsApp on my iPhone. I use it only for text messages, so I disabled camera, voice, etc. and, what I thought, was all sounds from it in the iPhone settings.

But once in a while, one of my older relatives decides to make a voice call to me. In that case the WhatsApp app starts playing this annoying ringing which I cannot kill, that is very frustrating especially if I'm at work.

Is there a setting (or some other way) to prevent it from ringing the incoming voice calls?

PS. I do not want to silence my phone completely. Just WhatsApp.

Edit: This is how the settings look like in WhatsApp:
In order to silence the ringer during an incoming WhatsApp call, you can turn off all the "Notifications," and prevent the WhatsApp from accessing your microphone by going to Settings > WhatsApp >Notifications. Please note that this will disable all the notifications on WhatsApp including the chat/message notification.   

 

If you'd like to receive sound notification for text/chat and only disable the ringer for incoming WhatsApp call, then you should disable the "Banner" alerts, and prevent the WhatsApp from accessing your microphone by going to Settings > WhatsApp > Notifications.