Q: My iPhone keeps receiving a message stating that someone is attempting to share my network and asking me if it's ok. I keep canceling, as clearly this is an unknown. I have recently changed to the new operating system. How do I stop this?

My iPhone keeps receiving a message stating that someone is attempting to share my network and asking me if it's ok. I keep canceling, as clearly this is an unknown and very questionable.  I know that the person is located in NJ from the details I picked up, but it's one of those odd "zd123" type of numbers. I have recently changed to the new operating system and fear that my phone is under attack from a hacker. I just shut the phone off for a bit. How do I stop this?