If this is a pad wear problem it is not covered by the warranty, wear items cannot be covered for obvious reasons. I doubt that this is the first set of pads, if it is you have done very well and needed new ones anyway.
Always look at the car and see if you can find the problem, when the service rep tells you it is so and so, how do you know he is not making it up? Always ask to see the old parts, if they do not have them you have to wonder why.