Shoprite Stamps Are A *******

I bought R500 worth of stamps from a lady who lives in the same old age home as my mom and dad. I did this because she obviously depends on the stipend she gets as a commission from her sales. To cut a long story short, the cash I used was for a bus ticket to Joburg. When I tried to buy my ticket with the stamps at Shoprite Money Market, I was told they are only for cigarettes, alcohol and grocery items. Shoprite stamps are a ******* and force you to buy specific items even though you pay cash for them. I will now make it my duty to advise people against them.