I had the same experience recently - they warped within a matter of weeks for no apparent reason. I tried to find out what brand they were and there was no writing on them whatsoever - which according to my parts guy was probably an indication that they were made in China. I replaced them with Balo rotors which have been great. I stuck with the old pads, more or less out of necessity in the circumstance, and contrary to conventional wisdom they have worked out fine.