Dis-Chem Customer Manager Jarr

I bought 3 Himalaya products in which you buy 3products and the cheapest is free. I bought them online which I had intentions to pay for regardless then on my checkout the grand total was below my expected value. I went to the store to collect and when I arrived to my surprise the invoice is the same as the one I received on email with the discounted value. The lady at the till asked her supervisor to come and assist because when she scans the products it gives a different value(grand total), the lady asked that can she just confirm with head office because she can’t just override the price without enquiring with the head office. Which I was comfortable with. Shortly I then received a call from Jarr which happens to be the customer care manager(his uncertain about what customer care is). He tells me that there’s a technical error with online purchases, I should rectify the discounted amount because it does not make sense and I need to be logical about it & he has 500 other customers that he needs to deal with. He commences to challenge me to pay the full amount which I had no problem in doing so but to be treated like a ***** simply because I received a discount online and make me feel guilty for their technical errors which calculates prices and then make me feel guilty as if I’m here to ***** and I just came in store(Dis-chem Bluebird) as an honest customer which is in possession of a dis-chem loyalty card. I feel disregarded by the Customer Care Manager. Sies!