Whatsapp Broken on Laptop After Upgrade to iOS12.1

This is map4 again. I finally called Apple Support and they helped me troubleshoot the issue. For some reason, when I tried to connect to the Mac App Store, following the links from within Whatsapp, it kept giving me the error I mentioned in my original post: "The item you've requested is not currently available in the U. S. store". When I called Apple Support, they remotely accessed my Laptop and had me click on the "App Store" from the Apple Menu (upper left hand corner of the screen). Once the app store window was in view, they had me type "Whatsapp" into the search window and hitting return. After hitting return, the Whatsapp icon showed up with an "update" button beneath. I clicked on that, and that fixed the problem. Apparently the App Store was downloading the update all along, but hiding it somehow and instead of showing the icon for the update, it was flashing the error: "The item you've requested is not currently available in the U. S. store". Go figure!!!