As tempting as it might be to shame the clan or person that has been offensive on these forums, please don't. It is against the rules. If you see offensive behavior please take a screenshot of it and send it to support via in game settings (cog icon) ---> Help & Support ---> Conversation button on the top right!
Give all the details you have of the player as it will help. Support will get to it and take the appropriate action.
In many cases support can't give you the result or action taken, this does not mean no action was taken.