As a developer I want to integrate an API that allows me to save complaint resolution details into the system, So that I can efficiently document and store the resolution actions for each complaint and ensure accurate tracking.
Acceptance Criteria:

API Integration:
The API should allow customer service representatives to send complaint resolution details (e.g., resolution notes, status updates, and next steps) directly into the backend system.
The API should support the following inputs: complaint ID, resolution details, resolution status, representative name, date/time of resolution, and any attachments related to the resolution.

Successful Submission:
Upon successfully sending the data, the system should return a success response with a status code (e.g., 200 OK) indicating that the resolution details have been saved.
The system should confirm that the resolution details have been recorded with a timestamp of when it was saved.

Error Handling:
If there is any error in submitting the data (e.g., network issues, invalid complaint ID), the API should return an appropriate error message (e.g., 400 Bad Request or 500 Internal Server Error).
The system should log error details for troubleshooting.

Resolution Status Update:
Once the resolution details are saved via the API, the complaint status should automatically update in the complaint management system (e.g., from “In Progress” to “Resolved”).
A notification should be sent to the customer if the status is updated to “Resolved.”

Audit Trail:
The API should record all changes and updates to the complaint resolution details for an audit trail.
It should store the user information (e.g., who updated the complaint resolution) along with the date/time of each change.

Multiple Attachments Support:
The API should allow attaching multiple files (e.g., screenshots, call logs) as part of the resolution documentation.
Each attachment should be properly tagged with the complaint resolution and easily accessible for review.
Security & Access Control:
The API should ensure that only authorized users (e.g., customer service reps, managers) can submit and modify resolution details.
Ensure data security and compliance (e.g., encryption for sensitive data).
Response Formatting:
The API should return a standardized response format with relevant details, including a success flag and any error messages, ensuring consistency for the front-end or other systems consuming the API.