Difficulty with upgrade

I am now trying for 5 weeks to do an upgrade with MTN after being a client for more then 15 years and using MTN as my service provider. Paying my account month in and month out, I now struggle to do upgrade online aswell as in store in Bethlehem. No one can assist me. Getting fed up with all their stories, if it is not the system then they just drop the phone on you without calling back. MTN's customer care and service are really going up in smoke.