few things you can do...
1. report the issue to Samsung Members app after you try to update the software again, Samsung tech people should be able to look into why your device isn't updating.
2. take it to your carrier after you back up your information then ask them to flash the device to latest version.
3. download Odin on your computer and flash it yourself after backing up your information.
But I suggest the 1st and try not to risk losing your information by accident