Did you say update? So your game was out-of-date before the Slug Club TLSQ? Here is the thing I've searched about your case, although there's not many, but apparently some people had reported they got banned after updating the game right after some event went live. I don't know the cause, and this is just a speculation, but the game's updater algorithm might deem such behavior suspicious so when they check your game's code, they'll find that particular account has been altered.
Also, I am sad to inform you, there's nothing we can do about your banned account. Otherwise, people here won't discuss on how to (hopefully) avoid ban and would play to their hearts content.