MTN retentions department unable to assist efficiently

On the 8/11/2017, I did an early upgrade on my cellphone contract because my current phone got damaged and I needed a smartphone urgently for work purposes. I was told the phone will be delivered within 3 to 7 days. I called the delivery company on the 14/11/2017 and they did not receive my order. I called MTN retentions and was told that the phone will be delivered by the end of the week. The order is still pending and the phone is still at the MTN warehouse. I immediately requested that the early upgrade be cancelled because I repaired by phone. I was told that an email will be sent to the warehouse for a RMA number and then the contract will be cancelled. I was told that it should take between 24 and 48 hours. I called in today 16/11/2017 and was told that they did not receive the RMA number and it could take 3 to 5 days. I was told that the person who sent the email will call me. This is unacceptable. Your call centre always gives the wrong information. I asked to be put through to a supervisor but was always given an excuse or was put through the previous person who assisted me. I asked them to call the warehouse but was told that they do not have a number. This is a simple request but MTN is making it so difficult. Please can someone call me and escalate the matter urgently.