There are generally two avenues available.
The first is to submit a second application correcting the errors or deficiencies of the first. To do so, you may have to make an Access to Information request to obtain the officer’s notes on your file and confirm the reasons for refusal.
The second, if you are satisfied that your file is being treated arbitrarily, is to take your file to the Federal Court to request the intervention of the Federal Court. You can do this from within Canada or from abroad.
We can advise you on these two options and give you the benefit of our experience in this area.