http://forum.1cpublishing.eu/sendmessage.php
Click "other" and type in: Requesting account deletion
In the textbox write what you just wrote here and press the "send" button (not reset fields).
Alternatively write a PM to a moderator or post some more weird threads. Preferably some that violate the Forum rules so massively that they'll ban you permanently.
Another suggestion would be to just not type in forum.1cpublishing.eu in your browser and visit it anymore...