I bought 4 water bottle at R200 online at makro,after four days I received email from makro that the stock is finished they will refund me

I bought 4 water bottle at R200 online at makro,after four days I received email from makro that the stock is finished they will refund me.I send them email that I don't want refund because I saw that they have advertised the same water bottle again with different prices (R400).It shows that the stock is still there,Maybe the made mistake with the first price.