Hey @Fingersdaily,
Sorry to hear of the issues that you're having with your calls whilst roaming. Calls via Whatsapp would be over the data or wifi connections rather than the phone network
Does this happen in more than one country that you've visited?
Does this happen in a specific area or all over the country that you're in?
What signal strength do you have, when the calls come through?
Are you always connected to the same network?
Regards
Steven_L