If you wanna stop the printing process in Linux and having trouble using the GUI printing tools, you can always stop it using the terminal/console mode.
1. start up your terminal
2. type lpstat -v
(This command give the list of printer name available or installed in your linux system)
3. type cancel -a [printer name]
(cancels printing job of a specific printer; that is why we use the command lpstat -v first to know which printer should we stop)
if this does not work then instead typing lpstat -v we use lpq (which give the list of the printer that has a job in the queue). After that repeat step 3.
if this still does not work then the printing process is done through network. If so, locate the computer and stop the printing process there.
hope this help a lot cause it does to me Big ^_^.