I use the hotspot on my iPhone 7 for internet access on other devices. For the past 3 weeks I've had to change my password about 3-5 times a day due to mysterious connections on my hotspot. Within a hour of password change another connection will appear. At least a dozen times I've looked at the iPhone and it says 2 devices are connected when they should only be one. When I pick up the phone and look into the camera the connections disappears. Call my phone provider the supervisor said the same thing happened to her. She said to file a police report which I did today. Phone provider says there's no fix. So I went to the Apple store talked to the techs until they closed. They said they is no fix for someone hacking into you phone. Apple tech also said hundreds for people are talking about this in the Apple forum. My phone provider and Apple say the phone is being hacked.
Read more: https://iphoneus.org/faq/who-is-responsible-for-your-cellphone-being-hacked.html