What are charges for Harassment (Wisconsin)?

So, I got on this Minecraft server, and then they kicked me off for "being annoying, gross, childish," etc.
I decided to spam the applications with just silly things like "you know your server sucks" "shut down"
I was pretty mean. But they took my IP and threatened to call the cops. What could the cops do to me? I'm 13, by the way. I'm just worrying a bit that I made a rash decision.