New Category doesn't appear on front end

-- url of the page with the problem -- : www.thirdcoastcoffee.com/index.php
-- HikaShop version -- : 2.4.0
-- Joomla version -- : 3.4.8
-- PHP version -- : 5.3.29
-- Browser(s) name and version -- : Google Chrome

I am maintaining a website I didn't build, but adding a new product category should be normal maintenance of any online store.
Here's the problem: I created a new product category and published it and then created some new products within this category. These can be seen on the back end. But though the categories can be seen on the front in in the unfiltered array, the new category can NOT be seen on the front end.

4 categories previously existed when I inherited this site. They appear in a drop drown list under "Buy Coffee" tab (the HikaShop component). I will probably change this to "Buy Products" but first i need to add the new "Other Merchandise" category that I have just created and published.
On the back end there are 5 categories (including the new Other Merchandise category) and the products are correctly assigned to it.

In Joomla's Main Menu the original 4 categories are listed, but the new category is not listed. I don't know if I need to manually add the new category (Other Merchandise) to this list, but i also don't know how that would be done.

How can i get the new category to be included on the drop down list of product categories?

An update on my problem: I created a new Menu item named for my new category (alias properly associated with the category name) but the wrong subset of products is being displayed on this page!

On the back end, when I check the products, the new products are in the correct category which has ID 16; but the products that show up on my new category's page on the front end are old products that are associated with an old category ID 12. These producs are still correctly displayed on their category's page.

Where do I make sure the correct subset of products is shown on the front end? (I don't have any idea how another category of products became associated with my new category.)