RTT is failing to deliver my cellphone!!

I upgraded my MTN contract online and was told that my new handset will be delivered soon. Since it would be delivered at home and at that time I would still be at work, I told the Consultant that the delivery people MUST call me before making the delivery. To my surprise, i received a call from RTT consultant telling me that the delivery people were at my place to deliver but I was not available. I told the lady the same thing that they must call me before they deliver. I have been waiting for them to deliver but i keep on getting these same excuses. my question is \why are they not informing me about the delivery?". I called them again yesterday to change my delivery address to my workplace as it seems they are not willing to meet me halfway"