How can I fix my alba paper shredder model S360?

My daughter shredded her old bank card and when i went to use it it would'nt work. There was card and paper stuck in the teeth which I have removed as best as I can. It will go into reverse but just won't work when I put paper in to shred. I notice there is a small clip across the opening where you are supposed to shred credit cards could this be the problem?