Hey, I've come here to ask a question. About 30 minutes ago someone connected to my server and said he wanted to test a force op hack, I laughed it off thinking it was that book hack and told him to go ahead, when suddenly in the chat it said Server - Opped (his name). I quickly de-opped him and banned him and his IP. I was so shocked when in the chat it said Console - Unbanned (His name) and he joined and started laughing at my attempts to ban him. I quickly shot down the server. I gave no one access to my console, but afterwards I immediately changed password on my multicraft. I've started my server up again and nobody seems to be joining yet, but that was terrifying when he unbanned himself. Please explain how he did this.
PS: I sent a support ticket but they just said something about anti cheats, which I already have.