Advertise an item but no stock of the item

I have been looking to get a new contract & saw a deal in the MTN catalogue. I then went to my nearest store who had the same catalogue in their store however they tell me that the deal is not available at their store as they are a franchise. Why have the same catalogue in franchise stores if they can't offer the same deals??? Then I called all the direct stores in Gauteng and some in KZN and none of them have stock of the watch that is added on to the S6 Edge deal. What is really frustrating is I get told they have no idea when stock is coming in or get told to call back in a week to see if there is stock and nor are they able to sign the contract for me without having the watches in stock. Why advertise for an item and have a special and then not have stock of the item. Then by the time your stores have stock next month then the deal will be over. This is really bad service as I was planning on changing my network to MTN and right now I am thinking maybe I should take my business elsewhere. Really disappointed by this as customer service should be a priority in such a business