t9??

ok, so i know there's a post from a while back with this same question but the person's response isn't entirely correct, the damn phone doesn't save words for future use in t9 mode!  typing it out in abc mode does save it... but only for a few hours?  i'll go back later in the day and try to use one of the words i saved and it's like it... forgot it or something.  i've tried multiple times, same deal.  anyone else have this problem?