What do I do when I receive a message stating "Your system is heavily damaged by Four virus!"

My new Apple iPhone 6plus is giving me a very long message about a virus and damage to my phone. The message starts out with "Your system is heavily damaged by Fourteen viruses! We detect that your Apple iPhone is 28.1% DAMAGED because of four harmful viruses from recent adult sites. It goes on and says that my SIM card will corrupt my contacts, photos, data, applications, etc. Then it's stating that I need to install trusted VPN from the App Store for free.