GAC awarding improper banners

it's possible  even though you lost no battles you were less efficient then he was.,

Option 3: You do not understand how scoring works. If you dropped more than 20 banners than they did otherwise, this is possible. It would be helpful to know what league you are in and the exact scores if you want people to be able to address the possibility of cheating. 

You can always check the history when the week is over. 

Whether it's option 1,2 (or the likely) 3.  I think it would be a good idea to learn how banners work.  100s of times a week (I would guess) players win matches after losing more times; I've done it this season myself.

You're missing out on a large part of the strategy that is 'banner pinching'.  Some of the more efficient 'banner pinchers' have supernatural skills!