Lost "Add to cart" button after adding options

-- url of the page with the problem -- : www.rosmini.school.nz/shop/product/41-se...term-1-waterpolo-fee
-- HikaShop version -- : 2.6.1
-- Joomla version -- : 3.4.8
-- PHP version -- : 2.6.32-531.29
-- Browser(s) name and version -- : Chrome

After adding the options, we lost the add to cart button. Take a look at https://www.rosmini.school.nz/shop/product/41-senior-b-term-1-waterpolo-fee

This is how a regular product works: https://www.rosmini.school.nz/shop/product/42-premier-a

Also when a product is free, there there are options I would like it to say "Choose an option" instead. In which view and where can I customise this?

Hello,
You should set the "Display 'add to cart' button for free products" option to Yes via "Hikashop->System->Configuration->Main"

Ok, two more questions:

1. Is it possible to set it up (via a customised view or otherwise) so that they have to choose one of the options?
2. Which views do I customise if I want to add some PHP that will not display "Free" if there are options? (For now I will just edit the dictionary)

For option 2 I searched product / listing_price.php but could not find FREE anywhere