Was I handled unfairly, and does this “group chat” story even make sense?

I’ve(30f) been talking to a guy(33m) for a few weeks. We hadn’t met yet, and there was never any conversation about exclusivity. In fact, he specifically told me he wanted to take things slow and that there was “no pressure.”
Out of nowhere, he asked if I was talking to someone from Philly. I told him no because I’m not. He then told me I had come up in a group chat he was in and that people had shown him “recent messages” supposedly proving I was talking to another guy while talking to him.
I asked:
Who is this person?
What group chat?
Can I see the messages?
What’s this person’s name?

He refused to answer any of those questions or show me anything. He simply kept insisting that I was talking to this person, said he had screenshots of a conversation from as recently as “yesterday” (Tuesday at this point) and ended the conversation by saying he doesn’t compete and wished me good luck.
For context:
I’m single. I was having conversations with people because we had never discussed exclusivity.(literally only two other people) However, I genuinely have no idea who this supposed guy from Philly is because there isn’t one.
I’m attaching screenshots in the comments because I’m curious what other people think.

My questions are:
Does this sound like someone who actually had proof?
Has anyone ever experienced something similar with these random “group chats” where people supposedly exchange screenshots?
If this story were true, why refuse to tell me who the person was or show me what was supposedly said?
I’m honestly less upset that things ended and more confused by the whole situation.

For more context, we live 5 hours apart. We were supposed to meet for the first time today(Saturday). So a part of me believes it was some dramatic way of ending things instead of having a healthy conversation.

TL;DR: Guy I was talking to accused me of secretly talking to another man based on screenshots from a mystery group chat, refused to tell me who the person was or show me the screenshots, then ended things. I’m trying to figure out if this sounds legitimate or if I’m missing something.