I own a Trucksr Hat company and our sales have plummeted since we found out Wal-Mart is selling our product.

You have a potential breach of contract issue. If you have no reseller restrictions in your sales agreements with your customers why would my (assuming I bought from you) reselling the product you sold me, at whatever price I want, be illegal? If I bought 50 Big Macs from one McDonald's every day and sold them to my employees for $1 cheaper could another McDonalds down the street sue me because I was cutting into their profits for selling Big Macs for less? Will you not have to raise prices across the board if you dont contract your problem away?