Can't log into one of my chars

[Leandero]

2386063 - Leandero, ok visible in game
2486251 - LeanderoShield, visible and playable
2488183 - Spartacus, NOT hidden but not visible in the dropdown menu in game, name change greyed out
2488283 - Spartacus_, wanted to test if my account was bugged (any way to completely remove this one btw? )

I played on Spartacus for a week and got to lvl 25 without issues and all of the sudden i got an error that the id is in use, try to login again and my Spartacus just vanished, checked the servers and found a veteran crossbowman guy also called Spartacus.

I understand i have to change my name but i don't see any option to do that now as the name change is greyed out.

Thanks for your reply and hopefully we can resolve this, I wouldn't like to start over from lvl 1 again