Refund delay

In January I cancelled my month to month home WiFi and returned the device at MTN Hazyview. Thereafter I received an invoice that said I had a credit. I. February I called MTN call centre I was given a reference number BO*** and was told that I would receive my refund in 7 days. It's been months and I still have not received any refund. I then sent an email and the response I received was that I needed to go to an MTN branch where I returned the device in my case being Hazyview. I went to the branch and they told me I needed to speak to billing and they gave me their phone to use. I called MTN, the call was answered by retention who told me that they would transfer the call to billing. After the transfer an agent answered, I explained the reason for my call and she immediately transferred me. From there they kept transferring me from one agent to the other.

All I need is my refund and nothing else. Can someone facilitate my refund. I was a loyal customer who never missed payments. Can I get the same loyalty back from MTN