How did my Principal somehow unlock my locked phone?

Ok so I lost my phone while at school, and someone ended up finding it and returning it to the school office. I ended up getting called down to the office on the mic, and my vice principal asked me if this was my phone. She found this out by going on my contacts and finding out my name. She also texted some of my contacts/friends to find out how whose phone this was. What I don't understand is how did she gain access to my phone with a passcode on it? My passcode is not something easy like 1234, or 0000. It was actually just 4 random numbers. It makes no sense to me. Do schools have some kind of software hack to unlock iphones? Can someone please explain.

Why is my cord melting?

So my iPhone charging cord split awhile back so I put some electrical tape around it thinking that would be a good idea only to discover a week or 2 later the underneath the cord had melted off what should I do

What's wrong with my iPhone?

My iPhone screen has been cracked but I was still able to use it. However, my screen recently shut off and went blank. I thought my phone died but it would still vibrate even though the screen was black. Now it's just unresponsive. Anyone have any idea what could be wrong with it?