Fix Wordpress issue and refresh content - Existing Website

I have a very simple website with some basic customisations on a wordpress theme (Vantage/Infinity).
It is not loading since a week now, and this needs fixing (for both desktop and mobile, and responsiveness) - I have a backup from a previous version that i can share if required.

All the content is 80% ready. Once the fix is done, I will just review the content, and suggest a few changes in layout/content that need to be made and we are done.

It currently has the following pages/structure:
About Us
Blog
Products (Product 1 - Product 2 - Product 3 - Product 4)
Services (Service 1 - Service 2 - Service 3)
Contact Us
Home Page

This is how we proceed:
1. A short call where i explain the issue and give you access to the site
2. You fix the issue and ensure that the website loads on desktop and mobile
3. I review the content and give you a specific content update brief
4. You make these changes and once I am happy, we are done

Note that the Budget for this is fixed at $15.