Problem with stock

Im due for upgrade for almost 2 months now .I went in to cell c and called them a few times asking too upgrade but sadly everytime it comes to the where they ask what phone im looking for and i tell them I want the iphone 15 pro they tell me there isnt stock at the warehouse I understand but how can there be no stock for 2 months .and why are Cell c advertising the phone when they dont have it in stock .And its not the first time this happenned to me at cell c the first time was with the iphone 13 it was also November and the also told me there isnt any stock so i must wait and that time I waited 4 months so all i wanna know when are you gonna start working on this problem