Cell C Call centres

I was called by a cell c agent on 21 September 2020 and was told that I was eligible to upgrade my contract. After going through the necessary steps my contract was upgraded and I was told by the agent by the name of Jennifer that my new device will be delivered between 3 to 7 days. I have still not recieved the device. After calling about 20 times and holding on for hours on end I was finally told that there was no stock. How can Cell C offer you a device knowing well tjat they dont have stock. I eventually spoke to a Suraya from the retentions department who promised to escalate the matter and that if I was not contacted within the hour by management I should call back and ask for her. After waiting a few hours I tried to call Suraya but was told that there is no one there by that name.Bear in mind that each call takes about 20 minutes to be answered. I have been a cell c customer for many years and was always on contract.This service is not acceptable where I have to leave someone at home at all times waiting for the courier service and as a result my wife , daughter and I were staying at home taking turns to lose much needed wages.