loot from undaunted chest missing?

harrytree

So today on my vet5 toon i was in group finder whilst opening a gold key chest at the undaunted enclave i was happily surprised to see i had a kena shoulder in there, just as i was about to loot it i got ported into the dungeon and that was no worries i assumed id be able to grab it once i finished the dungeon, upon finishing the dungeon i went to collect my kena shoulder and much to my surprise there was no longer a kena shoulder there...

Is this a common problem? has this happened to anyone else before?
I submitted a ticket but i fear that like usual customer service will be no help at all.
What is the best way of going about following this up?