New charging failure

On the 4th of July 2020, we bought the iPhone XS at Apple Centurion Mall. Within 2 weeks the charging cable stopped working. Unfortunately we were then in isolation due to Covid19. On the 31st August 2020, I returned the cable and the service technician told me that the cable is out of warranty. Why? Because the pins have black marks on the and according to apple, they will NOT replace the cable. So I need to buy a new cable. We had the phone for 58 days and they refused to exchange the cable.