It is not possible to deactivate the WhatsApp Voice Call feature nor the Video Call feature, and we cannot comment on any future changes. Sorry for any inconvenience and thank you for your feedback.
A few tips for WhatsApp Calling:
- When receiving a WhatsApp Call that you do not want to answer, you can tap [Decline] or tap [Message] to send the caller a quick message instead.
- WhatsApp Calling is designed to use as little data as possible, but if you are concerned about data usage, answer calls when connected to Wi-Fi. Additionally you can enable [Low data usage] in WhatsApp [Settings] > [Data usage].
- If you do not wish to receive calls from a certain contact, you can block that person.