Terrible service - even for an existing client

Yet again I am dissapointed by Cell C's service. My last contract purchase didn't go well, at all, and now again they fail to deliver. Last week Wednesday (30 Apr), I called to buy a new data contract. Before I app****, I asked the lady (Lerato) how long it will take to get the device. She said 5-7 working days. My response was that it is too long, I needed it urgently - before the new month as my data contract is due to expire - so I would rather go into a Cell C store and get the device. She said she would make a plan and promised I would have the device by Friday (1 April). She assured me several times this would be the case. Needless to say - by Friday afternoon no delivery! I phoned again. The operator said they were out of stock... She said Lerato will call me back later that day. No call received. I called again yesterday morning (Monday, 4 Apr). Again they said Lerato will call me back, urgently. Again, I received no call! Pathetic service Cell C, and this to an existing client. How can you sell me a product that you do not have stock? Why do you appoint people lile Lerato? Perhaps it is better if I just renew my Vodacom data contract.