As you can see I used my email instead. :-/
I am about to ask the same question, I used a proper user name when registered to suse; when I navigated to this forum, it asked me to register again, I picked another user name, but it gave out error; I somehow accepted the default email, and surprise to see it used it as my user name! Now I found it's extremely difficult to change it. Nor could I find how to un-register myself. This is really bad!
had the same problem. i emailed cbran and he changed it for me
Thank you @blueacid ! I just found him/her and sent a message.
So you could do the same @firstname.lastname@example.org