When people try to make Their WhatsApp account, WhatsApp sends a code to their Mobile Number to Confirm Their Mobile Number. After verification, you are eligible to use WhatsApp services.
Some hackers use this method to hack your WhatsApp account and steal your data.
Reports say when a person try many times for Verify their Mobile Number. WhatsApp block their Text Service and give only Call Me option.
And then, when they click on Verify me via Call. One Robot calls them and Tell them a Verification Code. They write code and Verify their number on WhatsApp.
But if they didn’t Receive that Call. Robot tells them the code via Voicemail. And Hackers use this Voicemail to Access their Verification Code and Steal their Account & Data also.
WhatsApp are not say anything about this Bug yet. Hope they fix it soon.