I bought a pair of Philips Earhook SHS8100 Headphones off Amazon last September, and one day a few months ago the right earphone suddenly stopped transmitting any sound. The left earphone still works fine. I've tried to go through the process of obtaining a repair since I'm still within my warranty time limit, only I can't find the serial number at all. Is it meant to be on the earphones themselves, because all I can find is the model number. On the original case itself I cannot find any 14-digit string of letters and numbers that is supposed to be the serial number, either on the box or on any stickers. Apparently my product cannot be serviced out of warranty either. Does anyone know the serial number for my particular earphones, and if not, could anyone direct me to any Philips-sanctioned repair centres?