Web Developer to Fix Issue with Custom Built Site

ReachForTheStars.Today is a personalized audio meditations subscription service website that was built for us as a one-off project. Unfortunately, the original developer left the company we had contracted with and is not available to address an issue we are currently having with the algorithm which is at the core of the site. For a more in-depth explanation, view this document: ----------

WEBSITE TECHNICAL DETAILS
You will be given a 38-page handover document that was created prior to the developer leaving (a redacted portion of page one appears below) and he can answer questions if needed, although the replies tend to be delayed.

1. Environment Details for ----------
- Using ---------- for hosting the project.
- ---------- for Auto emails.
- ---------- (Frontend Gitlab Project & Backend Gitlab Project)
- Stripe payments

2. Technical stack (All the Technologies used to develop this project)
Frontend: Javascript React, Redux-Saga, React-Router, HTML, SCSS, Material-UI
Backend: Node.js
Database: MongoDB
Payment Gateway: ----------
Payment Integration: Stripe.js with backend and frontend.
Music Player: ----------
Authentication: JWT tokens

We are urgently looking for someone to fix this issue. Afterward, there are some additional changes we would like to make to both the frontend and backend (also detailed in the document) . While you are working on the site, you will need to send updates via email and attend a 1-hour Zoom call each week, currently on Tuesdays from 9am-10am Pacific Time.

Please include your resume + an individual estimate of how long you think it would take to fix the primary issue and make each of the changes we are looking for.

BONUS
We really want to implement some sort of Associate Program so that other therapists that have been trained by Success Center, Inc. have a financial advantage to encourage their clients to purchase a subscription. If you have any experience with this, make sure to let me know!