Stock Issues- Raincheck policy

Went to Makro Strubens Valley on 06/07/2018 to purchase a DSTV HD Single View decoder for R279 ( that was the last day of the promotion) only to be told my the sales person that there is no stock and why dont i take the one for R599 that comes with the dish. When i got home then i was told by a friend why did i not ask for a Raincheck (where you can get the product at the special price when the store gets in stock) . But by that time the store was closed. Why did the sales guy not inform me about this ? Does your staff not know about this process "Raincheck" Highly disappointed