Shocking Service

My contract became due for an upgrade. I proceeded to phone the Cell C contact number for upgrades and proceeded to speak to Palesa who advised me that I am eligible for the upgrade which I wanted. I was however informed that the stock of the device I wanted might run out so and she could not guarantee that I would get what I wanted. I advised Palesa that I would go to a Cell C Store and upgrade. I travelled to the Cell C Connect Centre on Maxwell Drive where I was duly assisted by Shepherd who proceeded to tell me after an enquiry with the accounts department that I was NOT in fact eligible for the device that I wanted to upgrade to.... even after I was informed telephonically by the Upgrades department that was eligible. This is honestly the worst service i have ever experienced. How can Cell C justify treating their existing clients like this?