I just picked up an XS MAX from the Apple store. I took it home, tried restoring my backup from ICloud and it proceeded to download IOS 12.3. It is now stuck at 'Verifying Update' and I have no way of rebooting the phone as a hard reset is not working. I can't even get on Apple chat because I need the serial number(this is a replacement phone so no box) which I don't have. Anyone have any idea what I can do?