Refused support for Apple Watch

In April 2019 I purchased an Apple Watch Series 4 40mm. The battery was faulty as it never lasted more than 8 hours, during the warranty period I went to Istore multiple times, and all they did was run a diagnostic and tell me there’s nothing wrong with the watch, 1 month before the warranty ended the watch started overheating when charging, it became unusable, I took it to Istore who then could not run a diagnostic on the device because it wasn’t paired with my phone. The warranty expired and the watch stopped coming on completely. After trying to get support from both Istore and Apple, their go to answer was that the device is ‘out of warranty’ and just quoted me to buy a new watch at full price. Clearly the watch had a problem from the start and I was just pushed around because no one wanted to help. And after warranty it’s easy to refuse to help because they have no responsibility. Apple Support also promised to call me back after my complaint, but never did. So disappointing after having owned more than 10 Apple devices in the last 10 years and R8000 wasted on a watch.