No exchange policy & terrible return process
You can't exchange products for a new size. You have to return the item and then buy the new size. And if you had a sale price originally, you won't get that price until after you have paid for the new one. It's a messy messy process. Do not order things that have a chance of not fitting, like rings, because getting the right size after a purchase is NOT trivial.
Also, the return process is designed to discourage you from returning anything. No matter how much you spend with them, you still have to pay for the return. Plus, it's only 14 days. If you have a busy life, it's so easy to miss the window by a hair.
Finally, Customer Support is so unhelpful. It's like they are charged by the character, so you get short, dead-end responses charged with apathy that don't answer your questions.