Contract upgrade

I am having a problem with cell c right now, they promised to deliver in 7 working days but 10 days later nothing and I had to call them to find out the device has been out of stock for 2 weeks. Which means I was **** to when I did my upgrade. The manager is not sure as to when will the device will be available, all they can say is sorry and its unfortunate. The service is unprofessional at its best, you can't be approving sales while you know you don't have devices on stock and not letting customers know well in time or during the time of upgrading that the device is not available and there is no time frame as to when it will be available.