Dior review: won't accept return

Bought 4 items from Dior. 2 Hoodies, hip pack and hat. Both hoodies were too small. I tried them on, and put them both back in boxes. I decided to return the hat and pack and exchange the 2 hoodies for large sizes. They won't refund/Exchange one of the hoodies saying I wore them. I NEVER wore them. I did try them on and put them right back in the box, but I never wore either of them. They say that it has a mark on the white hoodie and sent me a picture of a small dark spot on it. Whats crazy is I really never wore them. Ive opened a dispute with my credit card, but they say its my word against theirs. Its crazy. Ive never had any retailer deny me a return. I will never ever shop with Dior again.