Wow! Were there any differences in it that let you know it wasn't just a glitch?
Hi. Hacker here.
There is no way that you can copy a town through hacking. The only way someone could do that is if you yourself hacked your town and gave her a copy of your town file for her to inject into her game.
So, perhaps even weirder, this person has seen your town and manually copied in all of the details. Possibly through hacks, yes, but actually taking your town isn't possible.
Last, to everyone giving that person nightmare ratings, I suggest not stooping to a low level. For all we know, they may have not had any ill intentions whatsoever. They may have just really wanted that precise town to get to play in. So potentially trolling their dream ratings is unnecessary and, if anything, just puts you down to their level as if they purposefully maliciously jacked the town. "When they go low, we go high."