You've been scammed and have most likely purchased a stolen iPhone. Apple will not help you. We cannot help you. If you don't know or can't reach the owner who sold you the phone (who most likely is not the person who the phone is locked to), you've wasted your money on an iPhone you can NEVER use. If you can't get your money back, recycle the phone responsibly and chalk this up to a bad purchasing mistake. NEVER purchase an iPhone from someone you don't know or at least unless you could see the phone before purchase to ensure it opened to the hello page, indicating it was prepared appropriately for a new owner.
Sorry, but there is literally nothing you can do with this phone.
Read this --> The All Too Common SAD Reality of Buying … - Apple Community
Ps: Do NOT go looking for some service who claims they can get in the phone. They can't. And you'd be wasting more money doing so.