MTN - still waiting for the phone after upgrade

I upgraded my phone in May and I still have not received the new phone. When the courier company called to verify my details they said my date of birth did not match and they would fix with MTN. To date I have received no call from anyone. Since the upgrade is with MTN, I am holding MTN responsible for ensuring my phone gets delivered. I have been with MTN for 20 years and this is the first time I have a problem with the date of birth being incorrect.