Arbitration is your only option. No known work around. Submit a service request just so you can document how much it will cost and get them on the record denying your request for warranty. In the service request specifically ask for warranty repair so they have to address it and deny it. Then off to arbitration. You're only 4yrs out, is the manufacturer's warranty 3 or 4yrs? Probably doesn't matter, the last few posts I've seen they have been denying all claims as not covered b/c they label it a "cosmetic" issue. But, make them say this on your service request as well.