Poor customer service

<p>I've had a contact with MTN for 10 years now and have always been happy with the network until now. I was due for an upgrade on 8.10.2016 but delayed as I wanted the iPhone 7, after the phone launched I went to a store for the upgrade but had no luck with stock, MTN then called me to arrange upgrade and confirmed the had stock of the phone in the size and colour I wanted but when the phone was delivered it was not what I arranged for, the phone was then returned on 10.11.2016 and the upgrade cancelled to date MTN has billed and debited me twice for an upgrade I don't have, I have been battling for two months to get my credit from them and it's really very frustrating, I've probabaly spoken to 20 people already that's how many times I've followed up. I'd just like MTN to pay me the credit due to me. </p>