Samsung doesn't care about my warranty?

<p>I bought a Samsumg Galaxy Tab 4 a couple of months back, a couple of months into use I tried using a simcard in the sim slot. The tablet could not pick up the sim, or any other sim that I tried, where they all worked in my phone. I took my tab to a Samsung Care Centre in Pretoria... only for them to contact me a week later saying that I have to pay R1700 to fix the "mainboard", while my tab is still under warranty?! Its less than a year old, and I still have proof of purchase! Very unhappy with Samsung. How could I have possibly broken the mainboard as they call it?! I will never buy a samsung product again, because their warranties mean NOTHING!</p>