Sorry to hear this. If the officer isn't satisfied and they didn't say WHY they're not satisfied, think of the reasons why they might not be satisfied and address all of them. Some reasons could be:
-- The person writing your letter was not credible or was not in a position to know your duties
-- The job duties were described in a way that it was not clear to the reader that they are a match for your NOC (don't assume the VO understands your industry or its technical terms)
-- You did not match all of the duties mentioned in the lead statement (from other cases it seems they want to match the lead statement entirely rather than just "substantially")
-- You did not match enough of the duties in the description of duties
-- The VO wanted to see other supporting evidence (tax returns, pay slips, anything) and you didn't provide enough
Maybe you can think of some other possible deficiencies. You may consider asking for a clarifying letter from the person who wrote your original letter or a supporting letter from a second person. Go through the language to make sure it is absolutely clear to the reader who is not in your field that it is a match. Try to mention more of the duties if you can do so honestly. Provide as much documentation if you can especially if you have old documents from the company (internal memos, press releases, e-mails, project paperwork, anything) that would support your case.
Good luck!
