Bot uses your F-List name as your unique identifier in the system. This is your main link between the UFL and F-List. So, if you change your F-List character's name, this will break connection between your profile and your UFL character data. So bot will not recognize you anymore.
There's no way for you to fix it yourself, at least not at the moment. To fix this problem, you'll have to ask UFL bot's author, Wrecksler, to fix it in the database. For that you'll need to supply me with your old name and your new name, so I can find which character to fix.
You can also always just rename your character back, and everything will start working again :)