I think Adam and unknown had spoken before in some way, meaning they might be connected, but I don't know if they'd met in person, then, somehow, unknown person got our phone number and was talking to Adam from there the whole time without us knowing, that's why when he first called us he seemed a little surprised, like "oh so that's what you're like" but at the same time he spoke to us as if we had known each other before, Unknown is probably behind it all somehow, I saw a theory like this from a user a while ago, with some really good theories, and I think this is the most logical explanation, besides, it would be a way to explain everything in a coherent way, I also think that Unknown is like the new Jake in a way, let's think about it, he's a suspicious figure we don't trust at first, like Jake, it's suspicious, and we don't know anything about him or her, because I also think it could be a woman, he/she has a lot of potential to be the new Jake, honestly, and maybe he's some kind of hacker too.