I applied for a work permit in Canada,through a agent and i payed 1000 CAD,he provide me work permit after 1ye?

I applied for a work permit in Canada,through a agent and i payed 1000 CAD,He provide me work permit after 1year, Now he asking 3500 CAD before submitting the work permit in Canadian emby for visa , If i dint pay the money he saying he will cancel the work permit.what i should do,how i complaint about this issue in Canada,At the moment i am in Saudi Arabia please help me