FRONT BRAKES REPAIRS

AT 70000KM I HAVE CHANGED FRONT BRAKES FOR THE FIRST TIME, NOW 30000KM I WAS ASKED BY CMH TO CHANGE BRAKES AGAIN ASKING THEM WHY NOT AT 140000KM OR AT LEAST AT 130000KM, THE ANSWER I GOT FROM THE SERVICE MANAGER WAS \ IT HAPPENS"THIS IS NOT A CONVINCING ANSWER AND IT WILL NEVER BE. MIDRAND TOYOTA CHECKED MY BRAKES AND ADVISE THAT THEY WERE NEVER CHANGED"