Does not honour warranty

I got a Xiaomi Redmi Note 3 on a Vodacom contract in March 2017. The phone is great but in December 2017 I noticed dead pixels in the screen. This expanded to the top sixth of the screen blurring and green lines running down. Seeing that the phone is a few months old I took it back. The phone glass has no scratches, nevermind cracks, the back also, no cracks or scratches. This is due to my phone being in a thick protective back casing and tempered glass screen protector since I got it. I also never dropped the phone - this being evident that my 4 and 7 year old backup phones are still fine (I am careful with my electronics)

I also noticed that one of the LEDs on the dual flash also didn't work anymore.

I took the phone in to the only IC that is still open after my work hours, Sandton City (Job No 112148). After almost a month they told me my phone is back from repairs. I went back and the LED was apparently fixed, but the screen is not. This is because they can't seem to find stock, so it was labeled "uneconomical to repair". Then the IC assistant tells me that the phone was physically damaged from the inside, so I am responsible for the costs if it was repaired. How exactly is that possible? If the glass is fine, the back shell is fine, how can the LCD crack all the way through the phone. This is clearly a design flaw, or a most probably faulty LCD. I refused to accept the phone and demanded they send it back. I hope somebody from IC HQ reads this - if a device breaks within months due to a manufacturing fault, well within its warranty period and you cannot repair it because it is too pricey for you to order parts from China, then you REPLACE THE DEVICE.