Special Advertised but no Stock

Ive app**** for a new wi fi router contract. The special was on a router with a free 500G hardrive. Ive been approved and they printed the contract. When the went in their Stock room to go fetch my router and Harddrive I was told that they are out of stock and that I shoud come back the end of the month (September 2015). After a couple of weeks they phoned me back and told me that their stock has arrived but the special is no longer valid. Ive lodged a complaint at vodacom customer care a month ago and phoned them at least twice a week to find out how far they are with my complaint. First they said it will take up to 48hrs then they said 36hrs then a week then it is still pending then no one was assigned toit yet then thy said that someone has been assigned but they need to do a deeper investigation. On top of that they had a technical error last month (September) and the debit order of my other contract did not go off. Now they say their is no complaint on their system. If they had the stock on the special they advertised in the store this would not have happend now I dont get what I app**** for when the special was still running due to their lack of stock. Complaint no ***