Send back the snake, get a refund and let them handle the shipping back. YOU SHOULD NOT PAY FOR ANYTHING!! Let them send you a heat pack too.
I can't believe that they didn't inspect the snake before sending it. It won't take 5 mins to inspect for defects and mites. It's their name on the line. I understand that they have a lot of snakes to ship and take care of but that should not be a reason for poor quality control.