Cannot change long-expired contract

For years, I've been stuck with a contract that cannot be changed. The most recent incident is the store confirming that it will be changed within a few days...it is now 2 weeks later and on following up with the same store, they said nkthing was done. It seems their people just sit there pretending to help customers, wasting our time. Clearly Telkom doesn't want more business from its customers, 2 accounts already closed and another 2 about to be with 1 remaining...all of which could have been kept if they could just attend to my queries properly.