woocommerce site shop page grid not working with product categories

we have a site and on the SHOP page we need to display products by categories (not by products) when we select the option from customise/woocommerce/product catalog and we change to display categories it displays just 1 column (issue...we need 3 columns) but if we change the option to display products teh grid is 3 columns which is fine. The task is to display Categoris on a grid of 3 columns