What Can I Do If A Website Refuses To Honor Return Policy

I ordered a sweatshirt from GleeCustom. It’s supposed to be an embroidered sweatshirt with my dog on it. The shirt looks terrible. I bought it for my husband for Christmas. It looks nothing like my dog and it arrived with stains. I’ve been emailing them asking for a refund for two weeks they finally responded that the shirt wasn’t stained and they can’t help me. Completely ignoring that the dog on the shirt is not even close to the image I sent. Their website states they have a 30 day risk free return policy. They are based in London but shipped from China.