RCS Empty promises

I received a SMS on the 20th of March stating if i purchase for a certain amount using my makro credit card i will receive a voucher which i can use at Makro via SMS . I then made my purchase on the 27th of March making sure it's more than the minimum required amount however up till now i have not received my voucher and when i called RCS about this i was told they will get back to me and to date i am still waiting. Why offer something then you can't deliver. You make people believe you are giving them something just to get them to buy things and then you fail them like this....