Reactivating usename

[2fixThings]

Hi. I just tried to login and it keeps failing. I get username / password failure. Then I ask for password to be sent
to my email, and it says username / email failure. I try to register with my old username, tabbycatrobots, and it
says it is in use. So, how do I reactivate my username, tabbycatrobots. As soon as that is reactivated, I will
delete this new username. Thanks for any ideas and help.
Howard