Mr price robing their clients

I ordered two hoodies that where on promotion, They cancelled my order and refunded my money. when I clicked on reorder my items the price went from R296 to R404. when I phoned them to find out how they can do that, they made it out as if I'm lying and i must send them a screen shoot to prove I'm not adding anything else to my order or that i never changed my order. so I did, then i get a mail back saying that it was a limited offer and terms and conditions apply. If this is how they rob there clients, not to mention the once i ordered a hoodie which was to big, I had to exchange it in store, i took the exact same hoodie and they charged me extra to exchange it because it wasn't on special anymore And i made a big fuse in store