With the exception of large amounts of cash in notes of small denomination, profuse apologies and naming your first-born after the offended guide, I’m not sure what you can do to reverse a ban.
On the rare occasions when I have entered JC via the Flash option, the guides didn’t appear in green; this might have been the reason why you were unsure that you were talking to an authentic guide.
Try appealing to the guide’s better nature by sending a help email.
Good luck.