Bad Service

I app**** for an upgrade online after MTN system hounded me as my contract was expiring. It has been over a week and no response or feedback from MTN. I called the call centre on 3 days in a row and had no joy despite requesting manager to call me It appears that MTN have no managers on duty ever. The last call I was told that the online upgrade is handled by an external sub contractor and it was not their fault. I have been a customer for 27 years and now I am looking to migrate to Vodacom.