Angry 😠 😡 customer

I bought shoes boots at mr price online the was a sale, now I went to mr price secunda mall to exchange the size,since some of the boots don't fit well, they told me they can't change the boots cause the was no sale ,it was an era on the system 😳, I bought the boots and it's not my problem, m not happy/ angry with mr price ,it was their fault which I didn't know of now I must be involve,please fix this problem. Angry customer