WhatsApp Removed from the Windows store
WhatsApp has been removed from the windows store, after receiving numerous complaints from users especially those on Windowsphone 8.1, the developers of WhatsApp has opted to remove the App from the store. So search results in the store with either Windows Phone 8 or Windows Phone 8.1 return "We couldn't find a match try a different spelling or search term"
WhatsApp has not sent out an official statement on the when they will republish the app in the store, will keep you informed as soon as there is news on the update. In the mean time do not uninstall the app if you are still uses it