hmmm, a good result really then, maybe it was a problem with their seating, maybe they were vibrating? maybe they werent bedded in properly? or like you say, the pad could be at fault. difficult to tell over the internet. as for the pads, its worth a go, but mazda might say because you fitted them yourself, they arent coverd. that, or some over excuse for not refunding you. you never know though!