If you knew the cam-lock was not functioning properly, and continued to use the pannier it seems like you are responsible for the outcome. Why didn't you just buy a new cam lock for $25, and replace the faulty one? I'm glad that you were not injured.

https://www.arkel-od.com/en/cam-lock-hook-kit.html

The poor stitching is a quality item. That is why I've been using Ortlieb panniers for the last 10 years.