DVD player repaired 3 times, still not functioning

I previously reported my one faulty DVD player and received excellent service as well as a replacement unit. My father has now returned his 3 times and the player still switches on and off by itself. In other words, no progress. I wonder if they actually do any repairs or testing at these facilities. I realy think there is a huge problem with the repairs services that is supp**** by the Samsung. Hopefully this poor service recovery can be attended to as a matter of urgency as most of my friends and family all buy Samsung but lost all faith in the quality of the product due to this failure in the after services delivery.