Add Overflow Item System or Allow GMs to Assist With Lost Items

I know what you're thinking from the title - GMs can already restore an item, once per account. However, they can only assist you if this item actually entered your inventory in the first place.
In most situations, there's no issue with this, unless you're like me.
I cleared UCOB with my group the other day, and my inventory was full, so I never received the totem I earned. If this game were any other modern MMO with more modernized systems, the item would be sent to either an NPC (think like the Postmaster from Destiny, where you can recover items you've forgotten to loot) or to your mailbox like in World of Warcraft. Instead, the item simply vanishes, and I'm left with no way to receive the loot I earned.
I contacted player support to assist with the issue, and received a reply saying they were unable to assist me because the totem never entered my inventory.
This reply is ridiculous. You can see that I earned the achievement for clearing UCOB, and that a totem never entered my inventory, meaning I clearly should have had the totem but did not. It should be no issue to restore this to my inventory. What excuse is there for treating players who spend months at a time progging a challenge like that?

the game warns you about your open inventory slots as you get closer to filling it up. pay closer attention and manage your stuff properly.