Vodacom Voda bucks is a lie

I purchased kaizer chiefs jersey using my Voda buck and the Ref was sent to me and firstly when I do follow up to the courier they say they are out of stock they will contact me after getting stock and I must wait up to 3 months, and secondly today when I do follow up again they told me my order will be canceled because they can not get stock anymore, and now am confused because it's two different story now and I ask them if I don't call when should they call to inform me about my cancelation and they just drop my call. How can they sell something without a stock they are playing a robbing game and I want them to stand on their promises and give me what they promise.