1) are you showing up to all of the GNW battles? I know when I was leader, you only qualified for Legendary if you were at all of the fights. You can't show up to just 1 out of 3-5 battles and expect a Legendary pack.

2) If you are, then talk to your leader about it in group chat next time GNW happens (when most people are in game). Maybe you don't get because you haven't donated enough that week, or other reasons.

3) If you don't like the resolution of that, then take everyone who doesn't get the good rewards and make a new group. If they only have 3 or 4 people in the old group then they won't have enough activity to even be in GNW any more. But expect a lot of work, you will have to build the group up from level 1, no summons/skills/research again