Guild Wars 2

I received 2 chest simultaneously (WvW rank and the 10.5k) in a extreme lag fest fight in our garry against all 3 servers. I clicked both chest off the screen and continued with the fight. Later that night I was cleaning out the nights take, only to find the achievement chest was not there. I tried to log out and back in but it never came back up. The chest bar moved over to 11k so looks like 10.5k is gone. I haven’t had any problems so not sure exactly how to get this fixed. I submitted a report in game and here. Anyone know if this is common problem? Am I missing anything to get this fixed? Thanks!