Are you "Logged" onto the TMF?
When you get to the opening page of chat, do you enter your nic exactly as it appears as you or when you registered with the TMF?
I don't believe you can alter your nic in any way.
IF that does not work, off the home page of TMF scroll down to the Technical Support section and I am sure you will get all the help you need!
(short of psychotherapy...😉 😀 )
TTD😛 🙄 😉