worst service in my life

I received a call from cell c direct upgrade department on 10th July offering me an upgrade on one of my 5 contracts with cell c. I decide on a Samsung tab 4 10.1 inch and am told it should be delivered by Tuesday 14th July 2015. Tuesday comes and I phone 084 145 to enquire about my delivery, to be told that they upgraded my contract to a Samsung A3 which I did not order. It then took them 4 days to cancel that incorrect upgrade and still the incorrect phone gets delivered. The A3 gets sent back on thursday 16th July. I then phone cell c upgrades again and the correct device (tab 4) is upgraded and i am told that it may be delivered the following day (friday) or monday. On Friday i phone just to find out if it will be delivered to be told 8 days after I did the upgrade that there is No stock of the Samsung tab 4 10.1 inch! Not once in the 8 days did anyone mention a problem with stock. On Monday (today) 20th July I phone to enquire about a tab 3 10.1 inch and guess what?! Also No stock! I have never in my life experienced such revolting service and What's worse is I actually worked for cell c for 4 years!! I don't feel like upgrading to be honest so please sort this out ASAP!