Keep it simple. Talk to Samsung or carrier and be clear you want a fix or refund so you can try again.
Also, post in the XDA Forums where many deep dive into these issues. Be aware they may fix it by installing a new ROM.
My Galaxy A3 2017 passes its OTG check confirming it's USB OTG enabled but when I connect a brand new OTG cable and FAT32 usb memory stick it doesn't detect it. I've tried downloading, installing and running every otg troubleshooting app. None of them detect it and none of them tell me how to fix the problem. Only possible answers seem to me to be that either the OTG cable is faulty or there is some tweaking I need to do with the phone's usb driver - although it surely wouldn't be passing the OTG check if that were the case?. Any suggestions as to how I can test the former or pursue the latter (Since both are brand new it cheeses me off no end that they are not doing what they are supposed to do).