Last night my iPhone 7plus was working perfectly fine, until the screen went black. The button was still vibrating, but the screen would not turn back on. I plugged it into my computer and restored it, but nothing changed. It also said that my apple ID had been locked for security reasons. So today I took it to the apple store. The guy helping me ran some tests and was able to get my apple ID unlocked, but the phone was still broken. He looked over some of the things that were coming up on the iPad he was using before telling me that he was going to need to take my phone and send it to some secret technical services facility in Texas or Tennessee. He didn't explain what they did or what they were going to do, but he did say that the facility was secret and they never inform the apple store of what they are doing to my device once they get it. He mentioned they would be able to see if my device was being tampered with or hacked. What does this mean? It sounds serious to me, but I do not know much about phones are anything he was really talking about. Does anyone know what is going on or have had a similar experience? He made it sound like this sort of thing doesn't happen often.