What does it mean when a phone site says free activation?

Before y'all call me dumb. I was just making sure because I recently bought a iPhone from boost mobile for like $211 it said "free activation" but when I looked up reviews on YouTube they said how new users had to pay like $60 extra and they had gotten the same deal as me! So now I'm just confused.

Who is responsible for your cellphone being hacked?

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.