From the TIS info page here https://www.newtis.info/tisv2/a/en/
Fill in a feedback form and you might be surprised by getting a result allowing you to enter a personal password to regain access.
They make a point of banning you passing on any password you may receive and do not encoruage putting links to their site to pages on forums or message boards. If you do they monitor and will delete your user if you dont abide by their rules.