Poor service received from Vodacom call cantre, since November last year I'm not able to get an answer as to when my upgrade will be effective

Poor service received from Vodacom call cantre, since November last year I'm not able to get an answer as to when my upgrade will be effective. I called several times and no one can assist me with getting the package migrated. They keep making excuses . I have requested to speak to supervisor but they not available to take my calls.