Hey Bradley,
this does not sound like you posted in the wrong category. The X-50 Series are now the PRO Series and they share the controller with the Original Series.
The SD card is accessible this way:
Please be aware that switching the controller off with the switch will not disconnect the internal power supply from power! You have to physically unplug the power cable!
To rewrite the OS image, you need a SD card writer and a pc to connect it.
The Onefinity Controller SD card image files are here:
(the *.img.xz files)
However before you do this, I would connect a USB mouse and / or a USB keyboard to one of the USB ports and see if it’s really frozen (or just the touch device is not working). Also you could attach an Ethernet cable (see image above) and log in via ssh and see if the controller responds.