Your Theme control's the visual appearance of your store, it's pages, your contact forms and some part's of the checkout process.
Here is a list of the areas that are under the Theme's control:
Theme Default and included Templates, such as the Product Page, Collection Pages and Contact Page
Home Page Sections
Some visual styling on the Checkout Page
Here is a list of areas that are outside of the Theme's control:
Shopify Admin settings, such as languages, currency , gift cards, shipping and customer notifications
App's, custom coding or any custom elements or Templates
Tracking systems such as Facebook Pixel or Google Analytics
Shopify's relay and server system
The coding and layout of the Checkout Page
For any issues in the second list, Shopify Support will be your best avenue for accessing Support and assistance. For anything in the first list, we are more than happy to investigate the issue.