MTN not stocking devices for which they are advertising deals on promotion

I wanted to upgrade my contract and asked about a combo deal of the Galaxy A31 + Galaxy Watch Active for R299pm over 24 months. I called in and the consultant advised me that they do not have stock of the watches thus cannot honor the deal. I asked him when they will be getting stock and he said he does not know. Surely, if they are advertising this deal, they should have an answer as to when they will have stock or at least put you on a waiting list.