I recently drove my wife's 2012 Mazda SP 3 and when I braked from 80 km/h the steering wheel vibrated violently and the car took longer than it should have to stop. You could basically say it had a brake failure. When I asked my wife about it she said she thought it needed a wheel alignment, and it had been like it since the last service. When the dealer checked it he said it was likely a disc issue, which they have had many of before and if it was less than 20,000 km they do it under warranty. They said it was very common. They told me they couldn't do it straight away, but that it was ok to continue to drive it until they could. I wasn't happy about letting my wife drive what I thought was an unroadworthy car, but got no sympathy from the dealer or Mazda when I contacted them. I find this situation unacceptable from an organization that prides itself on selling the so-called best small car on the market. They bust their ass when trying to sell you a car but when you want some good old customer service all you get is crickets in the background!!!
I would write a letter to the dealer principal setting out your complaints about their service and send a copy of the letter to Mazda. Follow it up by asking to meet the dealer principal and explain your dissatisfaction with their service to him face to face.