Worst service with an even worse phone.

Samsung South Africa must be as useless as Vodacom. I have upgraded to a Samsung Galaxy S10. The phone has given me problems since day 1 (17 Aug 2019). I returned the phone 3 times to Vodacom as an OBF but they have found nothing wrong and refuse to fix the phone or give me a new one. The third time it was sent in, it was sent to a Samsung repair centre and still they couldn't find a problem (even though I had videos proving how it randomly rebooted itself and how the apps kept crashing.) As my last resort, I phoned Samsung call centre on the 27th September and told me story. I was told that I would get a call back from a product specialist. It's been a few days and the only call I received from Samsung was to rate the call that I had made. I have also sent an email to Samsung which I'm yet to receive a response to. What I don't understand is that this problem that I'm having with my S10 is a WORLDWIDE problem so how is there no solution to fixing the S10 or giving me a new phone?