Updated
Feb 26, 2019
The Superior Key from Dewey has been fixed, but the replacement for the key you've already owned before today's patch will be done during the next maintenance. We apologize for the inconvenience and ask for your patience.
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Dear Players,
We are aware of the issue where "Superior Key" from Dewey(Event Merchant NPC) is unavailable to use. We will fix this issue during the next regular maintenance. The superior key that you've already owned will be replaced with a usable item, so please keep your existing key until next maintenance.
Sorry for the inconvenience and thanks for your patience.
EOS Team