Samsung cell phone.. refusal to take responsibility

I bought a Samsung J8 cell phone on 31 August 2018 from the Samsung store in Canal Walk for R5999. According to my receipt the warranty expired ayear later. In mid-July 2019 I found the phone wouldn't take a charge. I tried different chargers and plug points and took off the phone's protective cover to see if I could see anything wrong. This is a separate plastic cover that I had bought separately. While doing this, I scratched the back of the phone inadvertently with my nail....a very light and superficial scratch

When I went in to the same store to ask what could be done, I was referred to the WEfix store also in Canal Walk. They examined the phone and sent me a quote for R3 918 to repair it. I was told the warranty was voided because of "damage" to the phone. (the light scratch)

I understand that legally Samsung is possibly within its rights to void the warranty, but I am querying whether ethically this is fair. The phone stopped working within the warranty period and the very slight scratch occurred after this event . There is therefore obviously an inherent fault with the instrument and to rely on a warranty clause to avoid responsibility by refusing to replace or repair it seems to me to be inappropriate and poor customer service.. I have been a loyal customer of Samsung over many years and many phones (in fact, I am using a new J6 plus that I acquired with my latest contract)

It doesn't make sense to repair the J8 at that price..I have lost some of my data that is on the hard drive of the phone and am very upset by the whole situation. I have had several phone call with their customer service deaprtment and also sent several emails. This is terrible customer service.