I bought a KMC X10 SL chain recently and after about 4 rides, admittedly in poor weather, it started to rust really badly.
I had cleaned and lubed it after every ride so it was a bit weird really.
I contacted the distributors in the Netherlands and was asked to send it over so they could check it over and I was told that it was really unusual.
Pleased to get an email fairly quickly offering me a replacement and was even offered the gold upgrade foc!
Received in the post this morning along with a couple of floaty key rings and some chain stay protectors!
Glad to find that excellent customer service does still exist.
Good on ya KMC!