Hey KoRno,

I take it you're playing on a Guest account, given that you see the 60 Days message and besides if the account is linked to Facebook or Google+ you won't be able to change the name as the social-account name takes precedence over all else.

If you PM me the User ID of your account I can check things on our end here.
You can find the User ID of your account by opening Top 11, then going to Settings and then switching to the Accounts tab to the right. It's a long number.