Information regarding breakpads

I bought a Ford Fiesta Ecoboost 1.0 in April 2017, today, 14.11.2017 the vehicle had to go for its first 20000km service. I received a call from Ford Rustenburg advising me that I only have 4.1% left on the break pads, when I called Ford South Africa speaking to Nelson, I told him my experience with my previous vehicles that I only replaced break pads on 80000km because I am not a hard breaker and I do not believe that these break pads should be worn to 4.1% if the car was fitted with correct break pads. I was advised by Nelson that there is a policy that cover defects up to 15000km and therefore nothing can be done because the mileage are over 15000km, however the service intervals are every 20000km, in my first 20000km I never felt anything strange when breaking therefore I never went to Ford Rustenburg to have the break pads checks. I am not happy with the advise and customer service received from Nelson, as I truly believe the break pads were not 100% full when the vehicle was bought as my sister confirmed she had the same experience when her Fiesta had to go for its first service and after the break pads were replaced she never had to replace it again, I truly believe that this is very poor quality break pads that comes from the Ford manufacturer. I was told by Nelson that I can go and fit break pads anywhere else as long as it is Ford approved otherwise I will loose my warranty on the vehicle, so basically I am forced to purchase these expensive break pads from Ford Rustenburg in order to keep my warranty.