I had the same problem. Haven't logged in for about 2 years and decided to return to the game due to not having fun in WoW or FFXIV anymore, found my account had been locked for security purposes, waited 4 days to get my account back. No idea what really happened or when exactly the account was locked. Worst part was that the password reset is valid only for 24 hours so if I had been away for the weekend like I planned I would be looking at resubmitting my ticket -.-