Bad service from a agent who is bring down the MTN brand

I have had very bad service from MTN SA. I recently dealt with Letta Selepe from the customer care team. I wanted to cancel my contract and she assisted me in upgrading rather. When I wanted to upgrade, she contacted and followed up every day until I agreed. Thereafter she advised that delivery of the device would take 3-7 days. It has now been 13 working days and I have been emailing and calling her unsuccessfully. She doesn't answer her phone or respond to emails anymore and I am currently paying for a device I don't have.

I'm also unable to get through to anyone at the call centre to assist.