In the letter it was written 'You have provided insufficient evidence to satisfy me that you have performed the action described in the lead statement, and a substantial number of the main duties of the occupation as set out in NOC 0112 Human Resource Managers.'
After that just the usual lines about providing 30 days to give evidence and six month's pay slip.
So in reply, I gave a cover letter with my promotion letters, company ID, company visiting card, some notices issued by me as part of HR duties, Letters issued from and to HR, few photos, recommendation letter from a colleague and a few other HR related docs by me. I could have provided more. Unfortunately i did not get the permission from the supervisor.
Initially my application had Reference letter by MD, salary account statement and job contract.
Hope my reply helps.