Unknown number keeps calling me?

I'm an 11 year old female. (If that helps) But they have been calling for the past two days once every hour. And i don't know if it's the same for iPhones and Androids, but on my iPhone when I click on a random number in my call logs and click the little circled i, it will tell show me the location the call came from, the time, and the number. But when I click the circled i for the unknown number, it shows NOTHING! All it says is "Unknown Caller". Usally i don't answer numbers I don't know of unless the numbers start off with my area code but I stupidly answered it and thought if I answered the unknown number they would leave me alone.So this last hour, they called about 10-15 minutes ago. So when I answered I said "Hello?" and it sounded like they screamed or mumbled. I don't know what it was, but it sounded VERY SCARY! Then they just hung up. Ik that they ll call again, I just know it, because if they were gonna leave me alone, they would ve did so when I first answered them the first day they called. And also there's no number to block, so what can I do? Should I tell my mom and dad? And I'm so scared and paranoid, that I'm scared to walk up stairs. I don't know why, but I think something is gonna jump out. (I'm so paranoid lol) But my room is downstairs anyways, I just go up there sometimes to look around, and plus my brother is up there. But fr, what should I do?

Dude tell your parents

If you see Unknown as the Caller ID, that just mean they are blocking the number from showing on Caller ID. You need to set your phone up, so that any number that is not in your contacts is automatically blocked, same for Private and Unknown. Have your parents download a call blocking app, that offers "Pick Up & Hang Up", so all incoming calls, that are not in your contacts, get hung up on without going to voicemail, if the default call app does not do that on your phone.