Not getting any answers, just passing the buck

I upgraded my cell phone contract on Friday the 11th of August 2017, I received my confirmation email from MTN with all of my contract details including courier company and contact details with reference numbers. I booked the delivery as an urgent one as the retention sales person Nancy Sekano advised we can do so and I asked if it would be possible to make the delivery date for Monday the 14th of August 2017 but ever since then I have been phoning MTN and DSV Couriers with my ID number and reference number but no one can pick up anything with either on their systems. On the 15th of August 2017 i phone again where they picked up something on the system with the reference number but it was registered in someone else's name and not mine. I then contacted the Manager at DSV couriers Palesa and to thus far she was the only one to get back to me regarding what is going but she could still not say what the problem is as she is still waiting for response from MTN. I know delivery takes up to 3 - 7 working days, but the fact that bothers me is that they offer an urgent delivery and don't deliver that and the fact that it's been 3 working days today and they don't have anything on the system is completely unacceptable. What is going on??? Can someone please give me an answer or anything??? PLEASE MTN OR DSV COURIERS!!!