Customized Shopify File Management App

I'm looking for a custom Shopify app to be made that meets the following requirements: I need a file management system that users require a log-in to access (if they're logged in to Shopify, that should suffice). Essentially, customers need to submit a request to the file system for a specific file, and I need to be able to reply with the file for the customer. They will also then need to reply to my correspondence, either with comments, notes, or by uploading additional files. I also need to have a database of files that customers can download, however they need to have "credits" available on their account (ideally purchased from the Shopify store itself) to be able to access these files. When the customer has credits, they can download the file, however they need to enter some specific details and the file needs to pass through an API to be coded with their specific details. In a perfect world, the customer will be able to enter their details on their user profile - and we would like it so that they can only edit them once to fix a mistake, otherwise they need to request a manual change to be made. The transcoding API will then pull this data to transcode the files at the time of purchase/download, rather than requesting it every time. Additionally, customers should be able to see how many credits they have available in their user profile, so that they know if they can use them to purchase a file, or if they need more. To purchase credits, the customer will buy them from our Shopify store, and this app should monitor orders to update a customer's profile with additional credits if they purchase them. It should also deplete credits when they're used for file requests. These options are only applicable to a small percentage of our customers - perhaps 1 in every 50 customers will need to have access to this system and/or the optional fields in their profile and the counter for credits. My initial thought is that when they first purchase credits, these options become available to them. Customers also need to be notified by email when a response to their "file request" has been added to the system, and there should also be a "traffic light" indicator as to whether they're waiting for us to supply a file, or if we're waiting on them to supply further information or additional files from the customer. When the whole process is complete, either the customer, or someone from our admin team needs to have the ability to mark the "custom file request" as closed. To give a more complete understanding: We are a company that does aftermarket ECU (engine control unit) reprogramming. We have customers that purchase a hardware device from us (we resell the device from a Korean manufacturer) and then we provide files for the customer to use. The file service is for two similar - but different - reasons: 1) It should act as a location where people can use their pre-purchased credits to buy pre-made engine control software files, which they can use their hardware tool to load into the car. The databased needs to be searchable and/or filter-able... or more ideally, it will only show files that have "version ID" that matches the ID that the customer has saved on their profile (some cars share the same ID in their ECU, these cars can use the same tune file) 2) People should be able to submit a request to the file service to be able to get a "customised file" from our tuning department. The request should essentially require them to fill out specific fields, check some checkboxes, and write a text-based request for anything "special" they want. We will then check our "admin dashboard" to see all the current custom requests from our customers and should be able to respond to them either with follow-up questions or with a file attached. The file that we attach should not be directly downloadable by the customer, nor should the files on the database. Files uploaded from the admin side will be one specific format, and when the customer purchases a file, it needs to be passed through an application/json (*.php) API from the Korean manufacturer (which will be supplied to the successful applicant) to transcode it to a different format, which will add their unique identifier information (from their user profile) to the file. Doing this locks the file to their hardware and means they can only use it in their car (i.e. they can't buy one file and share it with 10 of their friends)