MTN no stock of anything.

I'm due for an upgrade. I tried to upgrade on line. No one answers the what's app line and they claim they have no stock of any of the phones I want to upgrade to. Tell me quick: You advertise a whole lot of specials that are valid until 31 January, but you have no stock whatsoever. What I would call that is false advertising as well as poor service! No one calls back, no one answers the what's app line and all I get for an answer is no stock. I even tried calling 5 different MTN stores to find stock. Nothing whatsoever! But yet you advertise the stock? Prey tell how that works? Useless service from a useless network!