FASLE ADVERTISING!!!!

So I've been looking for a pair of headphones at the makro store and I bought one, but wasnt happy with it so I took it back because I saw a better one on the online makro store. I placed an order the Saturday night, today is Tuesday and I get an email saying Oops we made a mistake, The Makro online website displayed incorrect pricing for product(s) included in your order(s), and that they wanna give me a R100 for the inconvenience. I dont want there money I want what I paid for! Like how is this my fault? Iv been supporting them so long and they can go through my records to see! If this is the case then what's the point of me supporting them because they cant give me what I paid for! I have screen shots of the item advertised, because it's not there now. I just want what I paid for and I want this sorted out ASAP