Why have a promotion with no stock?

Telkom had a promotion in December 2018 for a laptop combo, so I went into the Mall at Carnival complete all the necessary documents just to be told they have no stock. I was advice to phone some branches on the east rand to find out if they have any stock, because with no success. Then in February 2019 they phoned me and said that I must come in on the 25th of February 2019 to collect the laptop combo, so I did just to be told that the warehouse have no stock. All the time, cost and effort for nothing. This is now three months and still waiting. WHY HAVE A PROMOTION!!!!!!!