I have found that a simple phone call can do wonders! Companies such as Hush Puppies has built a reputation which I am sure they want to uphold, so customer service and satisfaction is important to them. Their phone number is 1-866-699-7365 (M-F, 9:00 - 7:00). Here is a link to their site as well:http://www.hushpuppies.com/US/en-US/ContactUs/Form.mvc.aspx
I highly suggest a phone call rather than an email. Simply explain what happened (and it wouldn't hurt to say something like "I am a big fan of Hush Puppies and have never had this problem before.") and offer a solution (i.e., you will pay to ship the shoes back if they will send you a replacement pair or fix yours). Companies are more receptive if you already have a solution in mind rather than just calling to complain and vent. And no matter how rude the person on the other end of the phone is, maintain your composure and be abrupt but polite. If the person is not willing to help you (even if they say they are sorry but there is just nothing they can do), ask to speak to the manager/supervisor. ALWAYS get the name (first and last) of the person you are speaking with and make a note of it. If the manager/supervisor does not assist you to your satisfaction then keep moving up the chain.
If after all your efforts they still say "no," then repeat their names and let them know that you are going to report them to the Better Business Bureau (or whatever version you have in your country). Don't be surprised if they change their tune!
Good luck and "walk on!"