If you are in 'disagrement' with someone, then yes BL is the way to go.
If you feel someone has broken the rules please report them. https://www.warlight.net/wiki/Report
Making a forum post to call out someone is discouraged.
Based on your description it sounds like the only rule your opponent might have broken is related to coming with insults/chat behavior. I didn't open the game, but not surrendering is very much allowed.
Edited 9/2/2017 21:25:05