Do you share your account? If so, someone might of betrayed you and got you banned. Maybe a staff member was online and banned you straight away without a ban report.
Staff always have a reason to ban other players. The staff member must have been online to ban you for a specific reason.
To be player's can use fake messaging. One of my friends got banned because someone had a fake message of him saying he will ddos another play. But there is always a reason why staff ban players. Sometimes a player can use fake messaging on client's to make it look like there advertising. If there is a screen shot of this maybe look who took the screen shot then you can ask your self would this player really do this? Also innocent until proven guilty <3
When players use fakechat, only them can see it. If there is no report of you advertising, or at least you not being able to see the report since they may of sent a PM to a staff member, how would you know they were using fakechat?
If a player is banned and no player report is available, it is likely that the staff member responsible for the banning saw the player's rule violation personally.
Many low levels players have threatened to get me banned before and I never believed it and they said they would "hack me" and stuff like that but I never believed them until I got banned now.