How can I stop unauthorized FaceTime calls on my Devices?

A few nights ago, I received a missed FaceTime call from my mom around 4am. I asked her about it later that morning & she told me she never called me. I let it go & didn’t think much of it anymore. Then, around 11pm last night, I received a missed FaceTime call from one of my friends while my phone was on DND. I didn’t twice about it & didn’t bother calling back because I was headed to sleep. Anyways, I went to sleep & woke up around 3am to see TWO missed FaceTime notifications from that same friend & another one from my NINE year old?? Her tablet was in my room & she was sound asleep at the time I “received the call”… I also saw a login attempt from Kentucky. I’ve already changed my passwords & when I looked at my list of devices, there were only MY trusted ones so I’m really confused & creeped out by this. Does anyone know why this is happening???!!!

[Re-Titled by Moderator]