Then just try to register again, if it says "mail already registered" then just take another mail. Even you can register and make an account if you want. I just did it two weeks ago, because my landlady asked me to make my own TM30s so she doesn't need to do it all the time.
In TL you have to make the first move, so you have to go to your revenue office and ask for tax ID, and next year you will have to go to the revenue office again and ask for the tax filing forms. The revenue office will not inform you personally or send any letters. TIT