How is possible to buy the cilinders of my ativa shredder DQ121MDn?

I can fix my Ativa shredder DQ121MDn if I can put a new pair of diamond cut cylinders this machine use. The problem is where I can buy those cylinders? Office Depot doesn't have them because they said this item is not longer in their stores and I am trying to contact anyone in China where the manufacture company is and I don't know anyone there.