Hi,
Well, I didn't see any menu item when I arrived on the main page of your website and the only button was the "contact" button, while I was looking for a "shop" menu item or a product listing or a category listing.
Today, I checked your website again and I can see that if I click on that contact button, I can then see the menu area at the top with the shop menu item.
I would recommend to have that menu also display on your homepage.
Regarding your issue with the shipping being charged twice, that's because you have configured different warehouse for your products. So on the checkout, the products are grouped by warehouse and a shipping method has to be selected for each group. That's why you have to pay the shipping fees twice. Since you don't want that, I would recommend deselecting the warehouses you selected in your products so that they all are in the same shipping group.