Why is it So Hard to Block the “What’s App” Service in Windows Live Mail?

I know (because I looked) that this service is owned by Facebook. I do not have a Facebook account. There is no possible message (voicemail or otherwise) that I will ever receive from Facebook that could be anything other than SPAM or Malware. I have tried blocking it several times and it keeps managing to get around that.

This morning I finally marked it as a "Phishing Scam" in Outlook hoping that will get the Microsoft Engineers to take a closer look at that pestilential product and maybe shoot a message off to Zuckerberg telling him to do something about it because it's acting like a malware medium.