I think there's someone in Cerberus who already has your name, so you need to change your name. The name change will take effect after 24 hours.
I think you should send a ticket using the "Game Support" category. The Aeria Browser Team's respond might take up to 72 hours (3 days)
Here's the link.
D Yay! Divine for me and also 25% ammy
! Thanks for the prizes ^-^!