Hello you do not pay for an expired license you renew members access much like the old
vb licenses.
vb is the only place I know of know where you have to pay for a new license when each new code branch comes out.
Anyway if you want to uninstall classifieds you simply delete your classifieds directory on the server and to remove the tables just delete your classifieds tables from your database. they are usually prefixed by cp_ in a normal install