Not honouring Reward Card discount

My friends and I decided to spent the afternoon and early evening at Tsogo Sun's HydePark. When we requested for our bill, the waiter went to double check if we could use my TsogoSun Reward card for applicable discount. He came back saying we can't and we called for the manager on duty. A guy named Milan came and Asia the system is and has been offline and the discount cannot be processed. I feel that this is totally unacceptable in that why as customers have to be inconvenienced. This is utterly appalling and we have to be forced to pay the bill without discount or any concession. This is the second dram I am ever experiencing with TsogoSun and Rewards Cards. At this moment I do not think I should be telling my friends and family about this reward card at all because is it proving useless!!!!