This happened to my daughter and her friend as well. I've tested a fix and it makes a world of difference.
Flaky default FTDI Virtual COM Port (VCP) drivers included by Microsoft and Apple are a common pattern in these issues.
There's an FTDI VCP driver fix applicable to Windows machines:
There's an FTDI VCP driver fix applicable to macOS High Sierra:
I'm not sure about Linux distros. I haven't seen a lot of issues reported. The Linux drivers may be fine, but a similar approach to Windows and macOS (installing the latest genuine FTDI VCP drivers) should work for Linux as well.
On my iMac, I can repeatedly run the Factory Firmware Update and upload sketches after applying the macOS fix.
After applying the latest FTDI Virtual COM Port (VCP) drivers, you should be able to use Arduino IDE to update the firmware on the Jewelbot. If that doesn't appear to work, try hitting the reset button (a pinhole button on the side of the Jewelbot between the NE and SE LEDs hittable with a unfolded paper clip) and then running the Upload again. Your Jewelbot should show the rainbow sequence after that.
If you get there, you're all set. If not, you may want to reach out to Jewelbots. Definitely try to troubleshoot first, because a replacement Jewelbot won't fix your computer's drivers You'll just wind up waiting longer.