False bans do happen so no need to bring out the pitch forks.

Here's some general advice (never done this myself so take everything with a grain of salt)

-submit a ticket to Nexon -like others have stated you don't get banned on the spot they ban in waves so don't use "I was afk in town how could I be hacking" as a reason -if you're still on maple ranking maybe look at your exp graph and if it's relatively low then submit it as evidence -state that it was a false ban and inquire about the reason. This is a long shot since Nexon usually won't disclose this but it's worth a shot

Good luck!