When you purchase a product with a warranty, it's supposed to give you peace of mind knowing that the company stands behind its product. Unfortunately, this isn't always the case. Sometimes companies will refuse to honor a valid warranty. When this happens, there are avenues for reporting the problem.
Contact the Manufacturer
Report the problem directly to the manufacturer if the retailer refuses to honor your warranty. The Federal Trade Commission recommends doing so via certified letter with a return receipt requested. In your letter describe the nature of the problem with your product. Include the date of the purchase as well as the location where you purchased it. If applicable, include the serial or model number. Tell the manufacturer how you would like the problem to be resolved -- for instance, with a refund or a replacement. Include a copy of any receipts, guarantees, warranties or other documents related to the purchase. Do not include original documents.
Other Options
If contacting the manufacturer doesn't work, report the company you bought the product from to your local or state consumer protection office. You can also report the company to the Better Business Bureau via the online complaint form on its website. If these methods do not yield results the FTC suggests legal action. You can take a company to small claims court or file a lawsuit to force a company to make good on its warranty.