Better Business Bureau, BBB
The only trick to dealing with the Better Business Bureau is that you must deal with the BBB office in the region of corporate headquarters (of the company you are disputing). Your local BBB can give you this information. My standard procedure is to write the corporate office, BBB, and the state attorney general (in the state with the relevant BBB office). It doesn't hurt to let everyone know you have a problem. BBB eventually assigns you a case number and puts you in contact with a corporate representative. As a condition of belonging to BBB, businesses must respond. If you have a good case chances are good that it will be fairly resolved. If your case is weak don't waste BBB's time.