MTN always out of stock !

We have been wanting to upgrade our business contract with MTN on a Iphone 8 deal but everytime its the same story , there is no Iphones available, our Iphones are out of stock. How can you advertise something but never have stock? And this is at the beginning of the month so then there has to be stock , And how can every other provider have stock but not mtn? When I phone Mtn direct or any store they send you from post to pillar and still no one can help. Should i rather just go to a different provider? Seems like Mtn doesnt need business.