Job won't delete from admin or printer direct

I have a problem with a job that was sent from the mobile Xerox printing app. It was sitting processing on the printer blocking all other jobs. I've cleared all the other jobs but this one job refuses to delete from either the xerox admin or if I select it directly on the printer. It just stays as "deleting" for more than 2 hours now.

I have turned printer on and off, I've tried to update the firmware via network and get a printer "busy" message and I've tried to update firmware from the USB in the printer, but the job sits behind the one I can't delete.

How do I get rid of it and start printing again?