Horrible experience.

I have been with cell c since I got my first phone, I am 27. The customer service I have experienced now is absolutely horrible. I did an upgrade and was told I would receive my phone within 7 working days. After 7 working days I phoned and was told the phone is out of stock. Then I phoned a few days later and was told my phone is on it's way. Then I phoned again yesterday, suddenly the phone is out of stock again. I believe I originally did the upgrade on the 9th of December. Between then and now the phone was on it's way and then out of stock TWICE. I am still waiting for a supervisor to phone me back from the first time I was told it was out of stock. Then yesterday I tried to reverse the upgrade and cancel my contract. I was told no, they can't. So now they want to have me pay for a phone I haven't received. Cell C what is going on? If this is how you treat customers I'd rather go somewhere else.