Dischem kyalami corner

I bought a perfume on the 1st of September at Kyalami corner dischem at their 25% one day spring special, it was advised at R1095 and they overcharged me and sold it for R1265, I noticed the error when I got home,I then went in to make them aware of the mistake that they have done. The lady at that counter told me that it wasn't a mistake that their new system overcharges customers like that,I am very disappointed as I always buy my perfume there without checking my reciept. I now worry about everything that I buy there without checking my reciept all the time. Please correct this dischem as it is false advertising and would be viewed as de*****ing of customers.