If you are using page shelf, then by design all elements of the dimension on the page shelf will be shown, even if they don't relate to the currently selected page (i.e. even if there is no data for that combination of customer and product, en empty space will be shown). There is no way around that.
You might have some luck if you don't use page shelf and try filters or parameters instead.
thanks- I removed the page level filter, than I added a context filter for customer, which filtered the order lines.Works perfectly. thanks for the help