Options Missing in Appearance > Customize page

Hello everyone, I’ve been running into some major issue with customizing my website, and I can’t seem find the source of the problem.

Basically, some of the customization options that should be there in my Appearance > Customize page in the wp-admin dashboard is missing – More precisely, they are there for a split second as the page is loading, but disappears before I can change them.

Here’s the link of my website:

abysscomic.com