Contact Form 7 Will Not Show WP Category Hierarchy in Dropdown

Hello

I have a submit form for video urls on my website. Everything is working but I have “a lot” of categories (20 parent and about 4 to 6 sub-categories each). As there is so many I opted to use a dropdown to select a category for each video submitted.

Here is the problem, in the categories section, and menus on the site, the category hierarchy is maintained and displays exactly as they were created. But in the Contact Form 7 dropdown for the same categories, it is not showing any hierarchy… all the categories are simply listed in alphabetical order. This will be very confusing and cumbersome to a user submitting a video.

Does anyone know how to add a category dropdown option to a form that will retain (and list) the categories exactly as they are created in WP Admin with the correct parent and child categories?

The page I need help with: [log in to see the link]