out of stock and failure to upgrade on system

I've been calling cell c for the past week with regards to my upgrade. The specific phone i requested is out of stock. Some of the call centre agents advised that they not sure if they will be getting stock, the others advised that the phone is discontinued. Their booklet for April/May advertises the phone and says nothing about limited stock. That is false advertising. Anyway i decide to settle for a different phone after speaking to a retentions agent . They are unable then to do the upgrade as they say the security questions that their system comes up with are incorrectly answered. Previously i have had no trouble upgrading through the call centre, but now all of a sudden due to the new system questions its not possible to upgrade through the calll centre, i must go to a cell c store. I asked to speak to someone senior, i was told his in a meeting in waterval. They dont even have people to override their system. I understand security checks are neccessary, but this system of theirs is in my opinion problematic. If i go to the cell c store they will charge me an additional admin fee. I've been a customer with them for almost 10 yrs and this is the service i get.