[Plugin:WP eCommerce] After deleting a category old urls still avilable

I am using WP eCommerce and to solve duplicate content issues – caused by having products in more than 1 category – I deleted some categories and made sure products appeared in only 1 category. The duplicate content problem still remains as the old urls are still available i.e. /products-page/deleted-category/product.

Can anyone offer a solution to removing the old urls?

Thanks.