Please, you need to provide details on the nature of the problem you are having. Do not simply state that it does not work, you need to explain what you are experiencing versus what you expect.
When I test your page, I see 2 add to cart buttons. Each add to cart buttons successfully ads an item to the cart. They are both added on separate line items. I am not able to see a problem on the page, If you could give details on the problem you are experiencing it would be helpful.