Disappointed at clicks Vincent

Clicks advertised clicks 200ml juice 4for R25 but at the till the juices ring R12,50 . I'm a member of a facebook group named stockpile and ladies got these juices at clicks all over SA for 4 @ R12,50. This morning I went to Clicks Vincent , first I checked operating hours from the website and it was 08H00. I rushed to clicks and I was there just before 08H00 only to find out the times at the door are different they only open at 09h00 wednesdays and sundays. Waited for an hour for them to open and I got about 24juices only to be told at the till that I cannot get it at R12,50 because its system error. My argument was that system error is not my problem but clicks problem and I should be able to get it at that price because I have evidence that there are a lot of people that bought them at R12,50. The store mananger could not give me at that price and I understood her point but I still maintain that it's not my problem and I strongly believe that I should get it at that price . I wasted my time and petrol ☹☹