I HAD RECIVED A WORK PERMIT FROM CANADA LAST EARLY THIS YEAR BUT DU ETO SOME PERSONAL AND PROFESSIONAL PROBLEM I WAS UNABLE TO GO TO CANADA AND JOIN, NOW I WOULD LIKE TO APPLY FOR WORK PERMIT EXTENSION, I AM BASICALLY FROM INDIA, PLZ ADVICE AS HOW I SHOULD DO THAT

You cannot renew a work permit in the scenario described (i.e., where you were granted approval but never traveled to Canada). A new application would be required.