fix my joomla extension wich creates duplicate urls

hello i have an extension that generates articles automatically and store them in one category. however it creates duplicate urls [login to view URL] and [login to view URL] i dont know if its a problem with the extension itself, or my joomla, or menu settings.... i need someone who is able to fix this, and also remove all the wrong duplicate urls that were already created until now (please do not do a 301 redirection in htaccess) i want a clean fix. thanks for bidding and give a honnest price. if u are correct with price and work and are a joomla expert, we will keep working together on more projects.