No delivery on Black Friday deal contract

During Black Friday I app**** for one of the Mega Data deals. They then called back and I sent all the required documents, they then said it was approved and will be deliverd shortly. It has been more than two weeks and nothing has arrived. I have sent emails to customer support and the online shop and haven't even got a reply back. The call centres are just as useless as they only say sorry they cant help I should email the online shop, which doesn't even respond. At this point I might just as well cancel it. How can you advertise this big promotion for Black Friday and then just not deliver? It's ridiculous. There's a reason MTN is the lowest rated mobile network in South Africa.